Module: Ruby2JS::Filter::Vue

Includes:
SEXP
Defined in:
lib/ruby2js/filter/vue.rb

Constant Summary collapse

VUE_METHODS = 
[
  :delete, :destroy, :emit, :forceUpdate, :mount, :nextTick, :off, :on,
  :once, :set, :watch
]
VUE_LIFECYCLE = 
[
  :data, :render, :beforeCreate, :created, :beforeMount, :mounted,
  :beforeUpdate, :updated, :beforeDestroy, :destroyed
]
VUE_PROPERTIES = 
[
  :$data, :$props, :$el, :$options, :$parent, :$root, :$children,
  :$slots, :$scopedSlots, :$refs, :$isServer, :$attrs, :$listeners
]

Instance Method Summary collapse

Methods included from SEXP

#S, #s

Instance Method Details

#initialize(*args) ⇒ Object 



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# File 'lib/ruby2js/filter/vue.rb', line 25

def initialize(*args)
  @vue_class = nil
  @vue_h = nil
  @vue_self = nil
  @vue_apply = nil
  @vue_inventory = Hash.new {|h, k| h[k] = []}
  @vue_methods = []
  @vue_props = []
  @vue_reactive = []
  @vue_filter_functions = false

  @vue_setup = false

  super

  @exclude_methods << @vue_methods
end

#on_block(node) ⇒ Object

convert blocks to proc arguments



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# File 'lib/ruby2js/filter/vue.rb', line 978

def on_block(node)
  child = node.children.first

  # map Vue.render(el, &block) to Vue.new(el: el, render: block)
  if \
    child.children[1] == :render and
    child.children[0] == s(:const, nil, :Vue)
  then
    begin
      arg = node.children[1].children[0] || s(:arg, :$h)
      vue_h, @vue_h = @vue_h, arg.children.first

      block = node.children[2]
      block = s(:begin, block) unless block and block.type == :begin

      if \
        block.children.length != 1 or not block.children.last or
        not [:send, :block].include? block.children.first.type
      then
        # wrap multi-line blocks with a 'span' element
        block = s(:return,
          s(:block, s(:send, nil, :_span), s(:args), *block))
      end

      return node.updated :send, [child.children[0], :new,
        s(:hash, s(:pair, s(:sym, :el), process(child.children[2])),
          s(:pair, s(:sym, :render), s(:block, s(:send, nil, :lambda),
          s(:args, s(:arg, @vue_h)), process(block))))]
    ensure
      @vue_h = vue_h
    end
  end

  return super unless @vue_h

  if \
    child.children[1] == :createElement and
    child.children[0] == s(:const, nil, :Vue)
  then
    # block calls to Vue.createElement
    #
    # collect array of child elements in a proc, and call that proc
    #
    #   $h('tag', hash, proc {
    #     var $_ = []
    #     $_.push($h(...))
    #     return $_
    #   }())
    #
    begin
      vue_apply, @vue_apply = @vue_apply, true

      element = node.updated :send, [nil, @vue_h,
        *child.children[2..-1],
        s(:send, s(:block, s(:send, nil, :proc),
          s(:args, s(:shadowarg, :$_)), s(:begin,
          s(:lvasgn, :$_, s(:array)),
          process(node.children[2]),
          s(:return, s(:lvar, :$_)))), :[])]
    ensure
      @vue_apply = vue_apply
    end

    if @vue_apply
      # if apply is set, emit code that pushes result
      return s(:send, s(:gvar, :$_), :push, element)
    else
      return element
    end
  end

  # traverse through potential "css proxy" style method calls
  child = node.children.first
  test = child.children.first
  while test and test.type == :send and not test.is_method?
    child, test = test, test.children.first
  end

  # wunderbar style calls
  if child.children[0] == nil and child.children[1] =~ /^_\w/
    if node.children[1].children.empty?
      # append block as a standalone proc
      block = s(:block, s(:send, nil, :proc), s(:args),
        *node.children[2..-1])
      return on_send node.children.first.updated(:send,
        [*node.children.first.children, block])
    else
      # iterate over Enumerable arguments if there are args present
      send = node.children.first.children
      return super if send.length < 3
      return process s(:block, s(:send, *send[0..1], *send[3..-1]),
        s(:args), s(:block, s(:send, send[2], :forEach),
        *node.children[1..-1]))
    end

  elsif \
    node.children.first.children.last == :forEach and
    vue_element?(node.children.last)
  then
    # map forEach to map
    map = node.children.first.updated(nil, 
      [*node.children.first.children[0..-2], :map])
    node = node.updated(nil, [map, *node.children[1..-2],
      s(:autoreturn, node.children[-1])])
    begin
      vue_apply, @vue_apply = @vue_apply, false
      if vue_apply
        s(:send, s(:gvar, :$_), :push, s(:splat, process(node)))
      else
        s(:splat, process(node))
      end
    ensure
      @vue_apply = vue_apply
    end
  else
    super
  end
end

#on_class(node) ⇒ Object

Example conversion

before:
  (class (const nil :Foo) (const nil :Vue) nil)
after:
  (casgn nil :Foo, (send nil, :Vue, :component, (:str, "foo"),
    s(:hash)))



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# File 'lib/ruby2js/filter/vue.rb', line 85

def on_class(node)
  cname, inheritance, *body = node.children

  begin
    vue_class, @vue_class = @vue_class, cname
    return super unless cname.children.first == nil
    return super unless inheritance == s(:const, nil, :Vue) or
      inheritance == s(:const, s(:const, nil, :Vue), :Mixin)
  ensure
    @vue_class = vue_class
  end

  # traverse down to actual list of class statements
  if body.length == 1
    if not body.first
      body = []
    elsif body.first.type == :begin
      body = body.first.children
    end
  end

  hash = []
  methods = []
  computed = []
  setters = []
  options = []
  watch = nil
  el = nil
  mixins = []

  # insert constructor if none present
  if inheritance == s(:const, nil, :Vue)
    unless body.any? {|statement|
      statement.type == :def and statement.children.first ==:initialize}
    then
      body = body.dup
      body.unshift s(:def, :initialize, s(:args), nil)
    end
  end

  @vue_inventory = vue_walk(node)
  @vue_methods.clear
  @vue_props = []
  @vue_reactive = []

  # collect instance methods (including getters and setters) and
  # reactive class attributes
  body.each do |statement|
    if statement.type == :def
      method = statement.children.first
      unless VUE_LIFECYCLE.include? method or method == :initialize
        if method.to_s.end_with? '='
          method = method.to_s[0..-2].to_sym
          @vue_props << method unless @vue_props.include? method
        elsif statement.is_method?
          @vue_methods << method unless @vue_methods.include? method
        else
          @vue_props << method unless @vue_props.include? method
        end
      end

    elsif \
      statement.type == :send and statement.children[0] == cname and
      statement.children[1].to_s.end_with? '='
    then
      @vue_reactive << statement.updated(:send, [
        s(:attr, s(:const, nil, :Vue), :util), :defineReactive, cname,
        s(:sym, statement.children[1].to_s[0..-2]),
        process(statement.children[2])])

    end
  end

  # convert body into hash
  body.each do |statement|

    # named values (template, props, options, mixin[s])
    if statement.type == :send and statement.children.first == nil
      if [:template, :props].include? statement.children[1]
        hash << s(:pair, s(:sym, statement.children[1]),
          statement.children[2])

      elsif \
        statement.children[1] == :options and
        statement.children[2].type == :hash
      then
        options += statement.children[2].children

      elsif \
        statement.children[1] == :el and
        statement.children[2].type == :str
      then
        el = statement.children[2]

      elsif statement.children[1] == :mixin or
            statement.children[1] == :mixins
      then

        mixins += statement.children[2..-1]
      end

    # methods
    elsif statement.type == :def
      begin
        @vue_self = s(:attr, s(:self), :$data)
        method, args, block = statement.children
        if method == :render
          args = s(:args, s(:arg, :$h)) if args.children.empty?

          block = s(:begin, block) unless block and block.type == :begin

          if \
            (block.children.length != 1 and
              not vue_wunderbar_free(block.children[0..-2])) or

            not block.children.last or

            (block.children.length == 1 and
              not [:send, :block].include? block.children.first.type)
          then
            # wrap multi-line blocks with a 'span' element
            block = s(:return,
              s(:block, s(:send, nil, :_span), s(:args), *block))
          end

          @vue_h = args.children.first.children.last
        elsif method == :watch and args.children.length == 0 and block.type == :hash
          watch = process(block)
          next
        elsif method == :initialize
          method = :data

          # find block
          if block == nil
            block = s(:begin)
          elsif block.type != :begin
            block = s(:begin, block)
          end

          simple = block.children.all? {|child| child.type == :ivasgn}

          # not so simple if ivars are being read as well as written
          if simple
            block_inventory = vue_walk(block)
            simple = block_inventory[:ivar].empty?
          end

          uninitialized = @vue_inventory[:ivar].dup

          block.children.each do |child|
            if child.type == :ivasgn
              uninitialized.delete child.children.first
            end
          end

          # convert to a hash
          if simple
            # simple case: all statements are ivar assignments
            pairs = block.children.map do |child|
              s(:pair, s(:sym, child.children[0].to_s[1..-1]),
               process(child.children[1]))
            end

            pairs += uninitialized.map do |symbol|
              s(:pair, s(:sym, symbol.to_s[1..-1]),
                s(:attr, nil, :undefined))
            end

            next if pairs.empty? and @comments[statement].empty?

            block = s(:return, s(:hash, *pairs))
          else
            # general case: build up a hash incrementally
            block = s(:begin, s(:gvasgn, :$_,
              s(:hash, *uninitialized.map {|sym|
                s(:pair, s(:sym, sym.to_s[1..-1]),
                s(:attr, nil, :undefined))})),
              block, s(:return, s(:gvar, :$_)))
            @vue_self = s(:gvar, :$_)
          end
        end

        if statement.is_method?
          method_type = :proc
        else
          method_type = :lambda
        end

        # add to hash in the appropriate location
        pair = s(:pair, s(:sym, method.to_s.chomp('=')),
          s(:block, s(:send, nil, method_type), args, process(block)))
        @comments[pair] = @comments[statement]
        if VUE_LIFECYCLE.include? method
          hash << pair
        elsif not statement.is_method?
          computed << pair
        elsif method.to_s.end_with? '='
          setters << pair
        else
          methods << pair
        end
      ensure
        @vue_h = nil
        @vue_self = nil
      end
    end
  end

  # add options to the front
  hash.unshift(*options)

  # add properties before that
  unless hash.any? {|pair| pair.children[0].children[0] == :props}
    unless @vue_inventory[:cvar].empty?
      hash.unshift s(:pair, s(:sym, :props), s(:array,
        *@vue_inventory[:cvar].map {|sym| s(:str, sym.to_s[2..-1])}))
    end
  end

  # add mixins before that
  unless mixins.empty?
    hash.unshift s(:pair, s(:sym, :mixins), s(:array, *mixins))
  end

  # add el as first, if app has
  hash.unshift(s(:pair, s(:sym, :el), el)) if el

  # append methods to hash
  unless methods.empty?
    hash << s(:pair, s(:sym, :methods), s(:hash, *methods))
  end

  @vue_methods.clear

  # append setters to computed list
  setters.each do |setter|
    index = computed.find_index do |pair|
      pair.children[0].children[0].to_s ==
        setter.children[0].children[0]
    end

    if index
      computed[index] = s(:pair, setter.children[0],
        s(:hash, s(:pair, s(:sym, :get), computed[index].children[1]),
          s(:pair, s(:sym, :set), setter.children[1])))
    else
      computed << s(:pair, setter.children[0],
        s(:hash, s(:pair, s(:sym, :set), setter.children[1])))
    end
  end

  # append computed to hash
  unless computed.empty?
    hash << s(:pair, s(:sym, :computed), s(:hash, *computed))
  end

  # append watch to hash
  if watch
    hash << s(:pair, s(:sym, :watch), watch)
  end

  # convert class name to camel case
  cname = cname.children.last
  camel = cname.to_s.gsub(/[^\w]/, '-').
    sub(/^[A-Z]/) {|c| c.downcase}.
    gsub(/[A-Z]/) {|c| "-#{c.downcase}"}
  camel = "#{camel}-" if camel =~ /^[a-z]*$/

  if inheritance == s(:const, nil, :Vue)
    hash_keys = hash.map do |pair|
      pair.children[0].children[0].to_s
    end

    if hash_keys.any? {|key| %w(render template).include? key}
      # build component
      defn = s(:casgn, nil, cname,
        s(:send, s(:const, nil, :Vue), :component,
        s(:str, camel), s(:hash, *hash)))
    else
      # build app
      defn = s(:casgn, nil, cname,
        s(:send, s(:const, nil, :Vue), :new,
        s(:hash, *hash)))
    end
  else
    # build mixin
    defn = s(:casgn, nil, cname, s(:hash, *hash))
  end

  # append class methods (if any)
  class_methods = body.select do |statement|
    statement.type == :defs  and statement.children[0] == s(:self)
  end

  unless class_methods.empty? and @vue_reactive.empty?
    defn = s(:begin, defn, *process_all(class_methods.map {|method|
      fn = if method.is_method?
        if not method.children[1].to_s.end_with? '='
          # class method
          s(:send, s(:const, nil, cname), "#{method.children[1]}=",
            s(:block, s(:send , nil, :proc), method.children[2],
             *process_all(method.children[3..-1])))
        else
          getter = class_methods.find do |other_method|
            "#{other_method.children[1]}=" == method.children[1].to_s
          end

          if getter
            # both a getter and setter
            s(:send, s(:const, nil, :Object), :defineProperty,
              s(:const, nil, cname), s(:str, getter.children[1].to_s),
              s(:hash, s(:pair, s(:sym, :enumerable), s(:true)),
              s(:pair, s(:sym, :configurable), s(:true)),
              s(:pair, s(:sym, :get), s(:block, s(:send, nil, :proc),
                getter.children[2],
                s(:autoreturn, process(getter.children[3])))),
              s(:pair, s(:sym, :set), s(:block, s(:send, nil, :proc),
                method.children[2],
                *process_all(method.children[3..-1])))))
          else
            # setter only
            s(:send, s(:const, nil, :Object), :defineProperty,
              s(:const, nil, cname),
              s(:str, method.children[1].to_s[0..-2]),
              s(:hash, s(:pair, s(:sym, :enumerable), s(:true)),
              s(:pair, s(:sym, :configurable), s(:true)),
              s(:pair, s(:sym, :set), s(:block, s(:send, nil, :proc),
                method.children[2],
                *process_all(method.children[3..-1])))))
          end
        end

      elsif \
        class_methods.any? do |other_method|
          other_method.children[1].to_s == "#{method.children[1]}="
        end
      then
        nil

      else
        # class computed property
        s(:send, s(:const, nil, :Object), :defineProperty,
          s(:const, nil, cname), s(:str, method.children[1].to_s),
          s(:hash, s(:pair, s(:sym, :enumerable), s(:true)),
          s(:pair, s(:sym, :configurable), s(:true)),
          s(:pair, s(:sym, :get), s(:block, s(:send, nil, :proc),
            method.children[2],
            s(:autoreturn, *process_all(method.children[3..-1]))))))
      end

      @comments[fn] = @comments[method]
      fn
    }).compact, *@vue_reactive)
  end

  vue_collapse_pushes(defn)
end

#on_cvar(node) ⇒ Object

expand @@ to self



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# File 'lib/ruby2js/filter/vue.rb', line 1111

def on_cvar(node)
  return super unless @vue_self
  s(:attr, s(:attr, s(:self), :$props), node.children[0].to_s[2..-1])
end

#on_cvasgn(node) ⇒ Object

prevent attempts to assign to Vue properties

Raises:



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# File 'lib/ruby2js/filter/vue.rb', line 1127

def on_cvasgn(node)
  return super unless @vue_self
  raise Error.new("setting a Vue property", node)
end

#on_for_of(node) ⇒ Object

convert for_of back to forEach for conversion to map



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# File 'lib/ruby2js/filter/vue.rb', line 1098

def on_for_of(node)
  if vue_element?(node.children.last)
    process node.updated(:block, [
      s(:send, node.children[1], :forEach),
      s(:args, s(:arg, node.children.first.children.last)),
      node.children.last
    ])
  else
    super
  end
end

#on_gvar(node) ⇒ Object

expand instance properties like $options to this.$options



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# File 'lib/ruby2js/filter/vue.rb', line 1117

def on_gvar(node)
  return super unless @vue_self
  if VUE_PROPERTIES.include? node.children[0]
    node.updated :attr, [s(:self), node.children[0]]
  else
    super
  end
end

#on_ivar(node) ⇒ Object

expand @ to @vue_self



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# File 'lib/ruby2js/filter/vue.rb', line 1133

def on_ivar(node)
  return super unless @vue_self
  s(:attr, @vue_self, node.children[0].to_s[1..-1])
end

#on_ivasgn(node) ⇒ Object

expand @= to @vue_self.=



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# File 'lib/ruby2js/filter/vue.rb', line 1139

def on_ivasgn(node)
  return super unless @vue_self
  if node.children.length == 1
    s(:attr, @vue_self, "#{node.children[0].to_s[1..-1]}")
  else
    s(:send, @vue_self, "#{node.children[0].to_s[1..-1]}=",
      process(node.children[1]))
  end
end

#on_lvasgn(node) ⇒ Object

for computed variables with setters, map x= to this.x=



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# File 'lib/ruby2js/filter/vue.rb', line 1172

def on_lvasgn(node)
  return super unless @vue_props.include? node.children.first
  s(:send, s(:self), "#{node.children.first}=",
    process(node.children[1]))
end

#on_op_asgn(node) ⇒ Object

for instance variables, map @x+= to this.x+= for computed variables with setters, map x+= to this.x+=



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# File 'lib/ruby2js/filter/vue.rb', line 1151

def on_op_asgn(node)
  return super unless @vue_self
  if node.children.first.type == :ivasgn
    node.updated nil, [s(:attr, @vue_self,
      node.children[0].children[0].to_s[1..-1]),
      node.children[1], process(node.children[2])]

  elsif \
    node.children.first.type == :lvasgn and
    @vue_props.include? node.children[0].children[0]
  then
    node.updated nil, [s(:attr, s(:self),
      node.children[0].children[0]),
      node.children[1], process(node.children[2])]

  else
    super
  end
end

#on_pair(node) ⇒ Object

instance methods as hash values (e.g., onClick: method)



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# File 'lib/ruby2js/filter/vue.rb', line 1179

def on_pair(node)
  key, value = node.children
  return super unless Parser::AST::Node === value
  return super unless value.type == :send and
    value.children.length == 2 and
    value.children[0] == nil and
    @vue_methods.include? value.children[1]
  node.updated nil, [process(key), value.updated(nil, [s(:self),
    value.children[1]])]
end

#on_send(node) ⇒ Object

expand ‘wunderbar’ like method calls



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# File 'lib/ruby2js/filter/vue.rb', line 444

def on_send(node)
  if not @vue_h
    if node.children.first == s(:const, nil, :Vue)
      # enable React filtering within Vue class method calls or
      # React component calls
      begin
        vue_h, @vue_h = @vue_h, [s(:self), :$createElement]
        return on_send(node)
      ensure
        @vue_h = vue_h
      end

    elsif node.children.first == s(:send, s(:const, nil, :Vue), :util)
      if node.children[1] == :defineReactive
        if node.children.length == 4 and @vue_class
          var = node.children[2]
          if var.type == :cvar
            scope = @vue_class
            var = s(:str, '_' + var.children[0].to_s[2..-1])
          elsif var.type == :ivar
            scope = s(:self)
            var = s(:str, '_' + var.children[0].to_s[1..-1])
          elsif var.type == :send and var.children.length == 2
            scope = var.children[0]
            var = s(:sym, var.children[1])
          else
            return super
          end

          return node.updated nil, [*node.children[0..1],
            scope, process(var), *process_all(node.children[3..-1])]
        end
      end
    end
  end

  # map method calls involving i/g/c vars to straight calls
  #
  # input:
  #   @x.(a,b,c)
  # output:
  #   @x(a,b,c)
  if @vue_self and node.children[1] == :call
    if [:ivar, :gvar, :cvar].include? node.children.first.type
      return process(s(:send, node.children.first, nil,
        *node.children[2..-1]))
    else
      return super
    end
  end

  # calls to methods (including getters) defined in this class
  if node.children[0]==nil and Symbol === node.children[1]
    if node.is_method?
      if @vue_methods.include? node.children[1]
        # calls to methods defined in this class
        return node.updated nil, [s(:self), node.children[1],
          *process_all(node.children[2..-1])]
      end
    else
      if @vue_props.include? node.children[1]
        # access to properties defined in this class
        return node.updated nil, [s(:self), node.children[1],
          *process_all(node.children[2..-1])]
      end
    end
  end

  return super unless @vue_h

  if node.children[0] == nil and node.children[1] =~ /^_\w/
    tag = node.children[1].to_s[1..-1]
    hash = Hash.new {|h, k| h[k] = {}}
    args = []
    complex_block = []
    component = (tag =~ /^[A-Z]/)

    node.children[2..-1].each do |attr|
      if attr.type == :hash
        # attributes
        # https://github.com/vuejs/babel-plugin-transform-vue-jsx#difference-from-react-jsx
        pairs = attr.children.dup

        # extract all class names
        classes = pairs.find_all do |pair|
          key = pair.children.first.children.first
          [:class, 'class', :className, 'className'].include? key
        end

        # combine all classes into a single value (or expression)
        if classes.length > 0
          expr = nil
          values = classes.map do |pair|
            if [:sym, :str].include? pair.children.last.type
              pair.children.last.children.first.to_s
            else
              expr = pair.children.last
              ''
            end
          end
          pairs -= classes
          if expr
            if values.length > 1
              while expr.type == :begin and expr.children.length == 1
                expr = expr.children.first
              end

              if expr.type == :array
                hash[:class] = s(:array, *expr.children,
                  *values.join(' ').split(' ').map {|str| s(:str, str)})
              elsif expr.type == :hash
                hash[:class] = s(:hash, *expr.children,
                  *values.join(' ').split(' ').
                    map {|str| s(:pair, s(:str, str), s(:true))})
              else
                if \
                  expr.type == :if and expr.children[1] and
                  expr.children[1].type == :str
                then
                  left = expr.children[1]
                  right = expr.children[2] || s(:nil)

                  expr = expr.updated(nil,
                    [expr.children[0], left, right])
                end

                hash[:class] = s(:array,
                  *values.join(' ').split(' ').map {|str| s(:str, str)},
                  expr)
              end
            elsif [:hash, :array].include? expr.type
              hash[:class] = expr
            else
              hash[:class] = s(:array, expr)
            end
          else
            hash[:class] = s(:array,
              *values.join(' ').split(' ').map {|str| s(:str, str)})
          end
        end

        # search for the presence of a 'style' attribute
        style = pairs.find_index do |pair|
          ['style', :style].include? pair.children.first.children.first
        end

        # converts style strings into style hashes
        if style and pairs[style].children[1].type == :str
          rules = []
          value = pairs[style].children[1].children[0]
          value.split(/;\s+/).each do |prop|
            prop.strip!
            next unless prop =~ /^([-a-z]+):\s*(.*)$/
            name, value = $1, $2
            name.gsub!(/-[a-z]/) {|str| str[1].upcase}
            if value =~ /^-?\d+$/
              rules << s(:pair, s(:str, name), s(:int, value.to_i))
            elsif value =~ /^-?\d+$\.\d*/
              rules << s(:pair, s(:str, name), s(:float, value.to_f))
            else
              rules << s(:pair, s(:str, name), s(:str, value))
            end
          end
          pairs.delete_at(style)
          hash[:style] =  s(:hash, *rules)
        end

        # process remaining attributes
        pairs.each do |pair|
          name = pair.children[0].children[0].to_s
          if name =~ /^(nativeOn|on)([A-Z])(.*)/
            hash[$1]["#{$2.downcase}#$3"] = pair.children[1]
          elsif component
            hash[:props][name] = pair.children[1]
          elsif name =~ /^domProps([A-Z])(.*)/
            hash[:domProps]["#{$1.downcase}#$2"] = pair.children[1]
          elsif name == 'style' and pair.children[1].type == :hash
            hash[:style] = pair.children[1]
          elsif %w(key ref refInFor slot).include? name
            hash[name] = pair.children[1]
          else
            hash[:attrs][name.to_s.gsub('_', '-')] = pair.children[1]
          end
        end

      elsif attr.type == :block
        # traverse down to actual list of nested statements
        statements = attr.children[2..-1]
        if statements.length == 1
          if not statements.first
            statements = []
          elsif statements.first.type == :begin
            statements = statements.first.children
          end
        end

        # check for normal case: only elements and text
        simple = statements.all? {|arg| vue_element?(arg)}

        if simple
          args << s(:array, *statements)
        else
          complex_block += statements
        end

      else
        # text or child elements
        args << node.children[2]
      end
    end

    # support controlled form components
    if %w(input select textarea).include? tag
      # search for the presence of a 'value' attribute
      value = hash[:attrs]['value']

      # search for the presence of a 'onChange' attribute
      if value
        onChange = hash['on']['input'] ||
                   hash['on']['change'] ||
                   hash['nativeOn']['input'] ||
                   hash['nativeOn']['change']
        attr = 'value'
        if hash[:attrs]['type'] == s(:str, 'file')
          event = 'change'
        else
          event = 'input'
        end
      end

      # search for the presence of a 'onClick' attribute
      if tag == 'input' and hash[:attrs]['checked']
        value = hash[:attrs]['checked']
        onChange = hash['on']['click'] ||
                   hash['nativeOn']['click']
        attr = 'checked'
        event = 'click'
      end

      # test if value is assignable
      test = value
      loop do
        break unless test and test.type == :send
        break unless (test.children.length == 2 and
          test.children.last.instance_of? Symbol and
          not [:not, :!, :*, :+, :-].include? test.children.last) or
          test.children[1] == :[]
        test = test.children.first
      end

      if value and value.type != :cvar and (not test or
        test.is_a? Symbol or [:ivar, :cvar, :self].include? test.type)
      then
        hash[:domProps][attr] ||= value
        args.push value if tag == 'textarea' and args.empty?
        hash[:attrs].delete(attr)

        # disable control until script is ready
        unless hash[:domProps]['disabled'] or hash[:attrs]['disabled']
          hash[:domProps]['disabled'] = s(:false)
          hash[:attrs]['disabled'] = s(:true)
        end

        # define event handler to update ivar on input events
        if not onChange
          if attr == 'value'
            update = s(:attr, s(:attr, s(:lvar, :event), :target), :value)
            upargs = [s(:arg, :event)]
          else
            update = s(:send, value, :!)
            upargs = []
          end

          if value.type == :ivar
            assign = s(:ivasgn, value.children.first, update)
          elsif value.type == :cvar
            assign = s(:cvasgn, value.children.first, update)
          elsif value.type == :send and value.children.first == nil
            assign = value.updated :lvasgn, [value.children[1], update]
          elsif value.children[1] == :[]
            assign = value.updated nil, [value.children[0], :[]=,
              value.children[2], update]
          else
            assign = value.updated nil, [value.children.first,
              "#{value.children[1]}=", update]
          end

          hash['on'][event] ||=
            s(:block, s(:send, nil, :proc), s(:args, *upargs), assign)
        end
      end
    end

    # put attributes up front
    unless hash.empty?
      pairs = hash.to_a.map do |k1, v1|
        next if Hash === v1 and v1.empty?
        s(:pair, s(:str, k1.to_s),
          if Parser::AST::Node === v1
            v1
          else
            s(:hash, *v1.map {|k2, v2| s(:pair, s(:str, k2.to_s), v2)})
          end
        )
      end
      args.unshift s(:hash, *pairs.compact)
    end

    # prepend element name
    if component
      args.unshift s(:const, nil, tag)
    else
      args.unshift s(:str, tag)
    end

    begin
      vue_apply = @vue_apply

      if complex_block.empty?
        @vue_apply = false

        # emit $h (createElement) call
        if @vue_h.instance_of? Array
          element = node.updated :send, [*@vue_h, *process_all(args)]
        else
          element = node.updated :send, [nil, @vue_h, *process_all(args)]
        end
      else
        # calls to $h (createElement) which contain a block
        #
        # collect array of child elements in a proc, and call that proc
        #
        #   $h('tag', hash, proc {
        #     var $_ = []
        #     $_.push($h(...))
        #     return $_
        #   }())
        #
        @vue_apply = false

        # gather non-element emitting statements in the front
        prolog = []
        while not complex_block.empty? and 
          vue_wunderbar_free([complex_block.first]) do
          prolog << process(complex_block.shift)
        end

        # gather element emitting statements in the front
        prefix = []
        while vue_element?(complex_block.first) do
          prefix << process(complex_block.shift)
        end

        # gather element emitting statements in the back
        suffix = []
        while vue_element?(complex_block.last) do
          suffix.unshift process(complex_block.pop)
        end

        result = s(:lvar, :$_)

        unless suffix.empty?
          result = s(:send, result, :concat, s(:array, *suffix))
        end

        @vue_apply = true

        if suffix.empty? and complex_block.empty?
          element = node.updated :send, [nil, @vue_h,
            *process_all(args),
            s(:send, s(:block, s(:send, nil, :proc),
              s(:args), s(:begin, *prolog,
              s(:return, s(:array, *prefix)))), :[])]
        else
          element = node.updated :send, [nil, @vue_h,
            *process_all(args),
            s(:send, s(:block, s(:send, nil, :proc),
              s(:args, s(:shadowarg, :$_)), s(:begin, *prolog,
              s(:lvasgn, :$_, s(:array, *prefix)),
              *process_all(complex_block),
              s(:return, result))), :[])]
        end
      end
    ensure
      @vue_apply = vue_apply
    end

    if @vue_apply
      # if apply is set, emit code that pushes result
      s(:send, s(:gvar, :$_), :push, element)
    else
      element
    end

  elsif node.children[0] == nil and node.children[1] == :_
    # text nodes
    # https://stackoverflow.com/questions/42414627/create-text-node-with-custom-render-function-in-vue-js
    text = s(:send, s(:self), :_v, process(node.children[2]))
    if @vue_apply
      # if apply is set, emit code that pushes text
      s(:send, s(:gvar, :$_), :push, text)
    else
      # simple/normal case: simply return the text
      text
    end

  elsif node.children[0]==s(:send, nil, :_) and node.children[1]==:[]
    if @vue_apply
      # if apply is set, emit code that pushes results
      s(:send, s(:gvar, :$_), :push, *process_all(node.children[2..-1]))
    elsif node.children.length == 3
      process(node.children[2])
    else
      # simple/normal case: simply return the element
      s(:splat, s(:array, *process_all(node.children[2..-1])))
    end

  elsif \
    node.children[1] == :createElement and
    node.children[0] == s(:const, nil, :Vue)
  then
    # explicit calls to Vue.createElement
    if @vue_h.instance_of? Array
      element = node.updated nil, [*@vue_h,
        *process_all(node.children[2..-1])]
    else
      element = node.updated nil, [nil, @vue_h,
        *process_all(node.children[2..-1])]
    end

    if @vue_apply
      # if apply is set, emit code that pushes result
      s(:send, s(:gvar, :$_), :push, element)
    else
      element
    end

  elsif \
    @vue_self and VUE_METHODS.include? node.children[1] and
    node.children[0] == s(:const, nil, :Vue)
  then
    # vm methods
    node.updated nil, [s(:self), "$#{node.children[1]}",
      *process_all(node.children[2..-1])]

  elsif node.children[0] and node.children[0].type == :send
    # determine if markaby style class and id names are being used
    child = node
    test = child.children.first
    while test and test.type == :send and not test.is_method?
      child, test = test, test.children.first
    end

    if child.children[0] == nil and child.children[1] =~ /^_\w/
      # capture the arguments provided on the current node
      children = node.children[2..-1]

      # convert method calls to id and class values
      while node != child
        if node.children[1] !~ /!$/
          # convert method name to hash {class: name} pair
          pair = s(:pair, s(:sym, :class),
            s(:str, node.children[1].to_s.gsub('_','-')))
        else
          # convert method name to hash {id: name} pair
          pair = s(:pair, s(:sym, :id),
            s(:str, node.children[1].to_s[0..-2].gsub('_','-')))
        end

        # if a hash argument is already passed, merge in id value
        hash = children.find_index {|cnode| cnode.type == :hash}
        if hash
          children[hash] = s(:hash, pair, *children[hash].children)
        else
          children << s(:hash, pair)
        end

        # advance to next node
        node = node.children.first
      end

      # collapse series of method calls into a single call
      return process(node.updated(nil, [*node.children[0..1], *children]))

    else
      super
    end

  else
    super
  end
end

#options=(options) ⇒ Object 



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# File 'lib/ruby2js/filter/vue.rb', line 43

def options=(options)
  super
  @vue_h ||= options[:vue_h]
  filters = options[:filters] || Filter::DEFAULTS

  if \
    defined? Ruby2JS::Filter::Functions and
    filters.include? Ruby2JS::Filter::Functions
  then
    @vue_filter_functions = true
  end
end

#process(node) ⇒ Object

if options is set, return an array of nodes



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# File 'lib/ruby2js/filter/vue.rb', line 57

def process(node)
  return super if @vue_setup
  @vue_setup = true
  if @vue_h 
    if node.type == :begin
      begin
        @vue_apply = true
        process s(:send, s(:block, s(:send, nil, :proc), 
          s(:args, s(:shadowarg, :$_)), 
          s(:begin, s(:lvasgn, :$_, s(:array)), process(node),
            s(:return, s(:gvar, :$_)))), :[])
      ensure
        @vue_apply = nil
      end
    else
      process s(:array, node)
    end
  else
    process node
  end
end

#vue_collapse_pushes(node) ⇒ Object

collapse consecutive pushes into a single call to push



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# File 'lib/ruby2js/filter/vue.rb', line 938

def vue_collapse_pushes(node)
  if node.type == :begin
    prev = nil
    (node.children.length-1).downto(0) do |i|
      child = node.children[i]
      if \
        child.type == :send and child.children[0] == s(:gvar, :$_) and
        child.children[1] == :push
      then
        if prev
          node = node.updated(nil, [*node.children[0...i],
            node.children[i].updated(nil, node.children[i].children +
              node.children[i+1].children[2..-1]),
            *node.children[prev+1..-1]])
        end
        prev = i
      else
        prev = nil
      end
    end
  end

  # recurse
  children = node.children
  children.each_with_index do |child, index|
    if Parser::AST::Node === child
      replacement = vue_collapse_pushes(child) 
      unless replacement.equal? child
        children = children.dup if children.frozen?
        children[index] = replacement 
      end
    end
  end

  node = node.updated(nil, children) unless children.frozen?

  node
end

#vue_element?(node) ⇒ Boolean

is this a “wunderbar” style call or createElement?

Returns:

  • (Boolean) 


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# File 'lib/ruby2js/filter/vue.rb', line 1191

def vue_element?(node)
  return false unless node

  forEach = [:forEach]
  forEach << :each if @vue_filter_functions

  return true if node.type == :block and
    forEach.include? node.children.first.children.last and 
    vue_element?(node.children.last)

  # explicit call to Vue.createElement
  return true if node.children[1] == :createElement and
    node.children[0] == s(:const, nil, :Vue)

  # wunderbar style call
  node = node.children.first if node.type == :block
  while node.type == :send and node.children.first != nil
    node = node.children.first
  end
  node.type == :send and node.children[1].to_s.start_with? '_'
end

#vue_walk(node, inventory = Hash.new {|h, k| h[k] = []}) ⇒ Object

gather ivar and cvar usage



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# File 'lib/ruby2js/filter/vue.rb', line 1230

def vue_walk(node, inventory = Hash.new {|h, k| h[k] = []})
  # extract ivars and cvars
  if [:ivar, :cvar].include? node.type
    symbol = node.children.first
    unless inventory[node.type].include? symbol
      inventory[node.type] << symbol
    end
  elsif node.type == :ivasgn
    symbol = nil
    symbol = node.children.first if node.children.length == 1
    if node.children.length == 2
      value = node.children[-1]
      symbol = value.children.first if value.type == :ivasgn
    end

    if symbol
      unless inventory[:ivar].include? symbol
        inventory[:ivar] << symbol
      end
    end
  end

  # recurse
  node.children.each do |child|
    vue_walk(child, inventory) if Parser::AST::Node === child
  end

  return inventory
end

#vue_wunderbar_free(nodes) ⇒ Object

ensure that there are no “wunderbar” or “createElement” calls in a set of statements.



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# File 'lib/ruby2js/filter/vue.rb', line 1215

def vue_wunderbar_free(nodes)
  nodes.each do |node|
    if Parser::AST::Node === node
      return false if vue_element?(node)

      # recurse
      return false unless vue_wunderbar_free(node.children)
    end
  end

  # no problems found
  return true
end