Class: JsDuck::Js::Serializer

Inherits:
Object
  • Object
show all
Defined in:
lib/jsduck/js/serializer.rb

Overview

Transforms Esprima AST into string

Instance Method Summary collapse

Instance Method Details

#to_s(ast) ⇒ Object

Turns AST node into string



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# File 'lib/jsduck/js/serializer.rb', line 8

def to_s(ast)
  case ast["type"]
  when "Program"
    ast["body"].map {|s| to_s(s) }.join

    # Statements

  when "BlockStatement"
    "{" + ast["body"].map {|s| to_s(s) }.join + "}"

  when "BreakStatement"
    "break" + (ast["label"] ? " " + to_s(ast["label"]) : "") + ";"

  when "ContinueStatement"
    "continue" + (ast["label"] ? " " + to_s(ast["label"]) : "") + ";"

  when "DoWhileStatement"
    "do " + to_s(ast["body"]) + " while (" + to_s(ast["test"]) + ");"

  when "DebuggerStatement"
    "debugger;"

  when "EmptyStatement"
    ";"

  when "ExpressionStatement"
    to_s(ast["expression"]) + ";"

  when "ForStatement"
    init = ast["init"] ? to_s(ast["init"]).sub(/;\z/, "") : ""
    test = ast["test"] ? to_s(ast["test"]) : ""
    update = ast["update"] ? to_s(ast["update"]) : ""
    "for (" + init + "; " + test + "; " + update + ") " + to_s(ast["body"])

  when "ForInStatement"
    left = to_s(ast["left"]).sub(/;\z/, "")
    right = to_s(ast["right"])
    "for (" + left + " in " + right + ") " + to_s(ast["body"])

  when "IfStatement"
    alternate = ast["alternate"] ? " else " + to_s(ast["alternate"]) : ""
    "if (" + to_s(ast["test"]) + ") " + to_s(ast["consequent"]) + alternate

  when "LabeledStatement"
    to_s(ast["label"]) + ": " + to_s(ast["body"])

  when "ReturnStatement"
    arg = ast["argument"] ? to_s(ast["argument"]) : ""
    "return " + arg + ";"

  when "SwitchStatement"
    "switch (" + to_s(ast["discriminant"]) + ") {" + ast["cases"].map {|c| to_s(c) }.join + "}"

  when "SwitchCase"
    test = ast["test"] ? "case " + to_s(ast["test"]) : "default"
    test + ": " + ast["consequent"].map {|c| to_s(c) }.join

  when "ThrowStatement"
    "throw " + to_s(ast["argument"]) + ";"

  when "TryStatement"
    handlers = ast["handlers"].map {|h| to_s(h) }.join
    finalizer = ast["finalizer"] ? " finally " + to_s(ast["finalizer"]) : ""
    "try " + to_s(ast["block"]) + handlers + finalizer

  when "CatchClause"
    param = ast["param"] ? to_s(ast["param"]) : ""
    " catch (" + param + ") " + to_s(ast["body"])

  when "WhileStatement"
    "while (" + to_s(ast["test"]) + ") " + to_s(ast["body"])

  when "WithStatement"
    "with (" + to_s(ast["object"]) + ") " + to_s(ast["body"])


    # Declarations

  when "FunctionDeclaration"
    function(ast)

  when "VariableDeclaration"
    ast["kind"] + " " + list(ast["declarations"]) + ";"

  when "VariableDeclarator"
    if ast["init"]
      to_s(ast["id"]) + " = " + to_s(ast["init"])
    else
      to_s(ast["id"])
    end

    # Expressions

  when "AssignmentExpression"
    parens(ast, ast["left"]) + " " + ast["operator"] + " " + to_s(ast["right"])

  when "ArrayExpression"
    "[" + list(ast["elements"]) + "]"

  when "BinaryExpression"
    binary(ast)

  when "CallExpression"
    call(ast)

  when "ConditionalExpression"
    parens(ast, ast["test"]) + " ? " + to_s(ast["consequent"]) + " : " + to_s(ast["alternate"])

  when "FunctionExpression"
    function(ast)

  when "LogicalExpression"
    binary(ast)

  when "MemberExpression"
    if ast["computed"]
      parens(ast, ast["object"]) + "[" + to_s(ast["property"]) + "]"
    else
      parens(ast, ast["object"]) + "." + to_s(ast["property"])
    end

  when "NewExpression"
    "new " + call(ast)

  when "ObjectExpression"
    "{" + list(ast["properties"]) + "}"

  when "Property"
    to_s(ast["key"]) + ": " + to_s(ast["value"])

  when "SequenceExpression"
    list(ast["expressions"])

  when "ThisExpression"
    "this"

  when "UnaryExpression"
    ast["operator"] + parens(ast, ast["argument"])

  when "UpdateExpression"
    if ast["prefix"]
      ast["operator"] + parens(ast, ast["argument"])
    else
      parens(ast, ast["argument"]) + ast["operator"]
    end

    # Basics

  when "Identifier"
    ast["name"]

  when "Literal"
    ast["raw"]

  else
    throw "Unknown node type: " + (ast["type"] || "nil")
  end
end