Collection Module

The Collection module provides utility functions for working with arrays.

Usage

Collect Class

The Collect class is used to create chainable collections for easy manipulation of arrays.

Before

items = [
  { a: 3, b: 1, x: [1, 2, 3] },
  { a: 1, b: 2, x: [] },
  { a: 2, b: 3, x: [2, 3] },
  nil
]

# Remove nil items
items.compact!

# Filter items where :a is greater than 1
items.select! { |item| item[:a] > 1 }

# Append { a: 0, b: 2 } if specified
items << { a: 0, b: 2 } if params[:should_append]

# Prepend { a: 4, b: 2 }
items.unshift({ a: 4, b: 2 })

# Sort items by :a
items.sort_by! { |item| item[:a] }

# Map items to new structure
items.map! do |item|
  {
    a: item[:a],
    b: item[:b],
    c: item[:a] + item[:b],
    x: item[:x].sort
  }
end

After

collect(items)
  .where_not_nil
  .where(:a, ">", 1)
  .when(params[:should_append]) do |collections|
    collections.append({ a: 0, b: 2 })
  end
  .prepend({ a: 4, b: 2 })
  .sort_by_key(:a)
  .map do |item|
    {
      a: item[:a],
      b: item[:b],
      c: item[:a] + item[:b],
      x: collect(item[:x]).sort.all
    }
  end
  .all

Example:

Filter

include ArrayCollection::Helper # Include collection helper to call collect only instead of ArrayCollection::collect.new

# Create a new collection
collect([1, 2, 3, 4, 5]).filter { |item| item > 2 }.all
# => [3, 4, 5]

Where

include ArrayCollection::Helper

# Create a new collection
collect([
  { name: 'Alice', age: 30 },
  { name: 'Bob', age: 25 }
]).where(:age, '>', 25)
  .all
# => [{ name: 'Alice', age: 30 }]

Where not nil

result = collect([1, 2, nil, 3, 4, nil, 5])
               .where_not_nil
               .all
# => [1, 2, 3, 4, 5]

index_of

collect([1, 2, 3, 4, 2]).index_of(2)
# => 1