Prototype JavaScript framework - Array

toJSON

2007-03-10T00:46:00Z

toJSON() -> String

Returns a JSON string.

Example


['a', {b: null}].toJSON();
//-> '["a", {"b": null}]'

toArray

2007-01-06T14:06:00Z

toArray() -> newArray

This is just a local optimization of the mixed-in toArray from Enumerable.

This version aliases to clone, avoiding the default iterative behavior.

size

2006-12-21T12:01:00Z

size() -> Number

Returns the size of the array.

This is just a local optimization of the mixed-in size method from the Enumerable module, which avoids array cloning and uses the array’s native length property.

from

2006-12-07T22:54:00Z

Array.from(iterable) -> actualArray

Clones an existing array or creates a new one from an array-like collection.

This is an alias for the $A() method. Refer to its page for complete description and examples.

inspect

2006-12-06T22:03:00Z

inspect() -> String

Returns the debug-oriented string representation of an array.

For more information on inspect methods, see Object.inspect.

Example


['Apples', {good: 'yes', bad: 'no'}, 3, 34].inspect()
// -> "['Apples', [object Object], 3, 34]"

Note

If you want to simply join the string elements of an array, use the native join method instead:


['apples', 'bananas', 'kiwis'].join(', ')
// -> 'apples, bananas, kiwis'

clone

2006-12-06T21:27:00Z

clone() -> newArray

Returns a duplicate of the array, leaving the original array intact.

Example


  var fruits = ['Apples', 'Oranges'];
  var myFavs = fruits.clone();
  myFavs.pop();
  // fruits -> ['Apples', 'Oranges']
  // myFavs -> ['Apples']

uniq

2006-12-06T21:22:00Z

uniq() -> newArray

Produces a duplicate-free version of an array. If no duplicates are found, the original array is returned.

Example


['Sam', 'Justin', 'Andrew', 'Dan', 'Sam'].uniq();
// -> ['Sam', 'Justin', 'Andrew', 'Dan']

['Prototype', 'prototype'].uniq();
// -> ['Prototype', 'prototype'] because String comparison is case-sensitive

Performance considerations

On large arrays with duplicates, this method has a potentially large performance cost:

Since it does not require the array to be sorted, it has quadratic complexity.
Since it relies on JavaScript’s Array.concat, it will yield a new, intermediary array every time it encounters a new value (a value that wasn’t already in the result array).

More efficient implementations could be devised. This page will get updated if such an optimization is committed.

reduce

2006-12-06T21:18:00Z

reduce() -> Array | singleValue

Reduces arrays: one-element arrays are turned into their unique element, while multiple-element arrays are returned untouched.

Example

[3].reduce();
// -> 3

[3, 5].reduce();
// -> [3, 5]

reverse

2006-12-06T21:04:00Z

reverse([inline = true]) -> Array

Returns the reversed version of the array. By default, directly reverses the original. If inline is set to false, uses a clone of the original array.

Example

var nums = [3, 5, 6, 1, 20];
nums.reverse(false)
// -> [20, 1, 6, 5, 3]
nums
// -> [3, 5, 6, 1, 20]

nums.reverse()
// -> [20, 1, 6, 5, 3]
nums
// -> [20, 1, 6, 5, 3]

indexOf

2006-12-06T20:58:00Z

indexOf(value) -> position

Returns the position of the first occurrence of the argument within the array. If the argument doesn’t exist in the array, returns -1.

Prior to version 1.6, Prototype’s Array#indexOf checked for equivalence (==) instead of identity (===). This was changed in order to be compliant with emerging browser implementations of Array#indexOf.

Minor note: this uses a plain old optimized indexing loop, so there’s no risk of extensions being detected by this method.

Example


[3, 5, 6, 1, 20].indexOf(1)
// -> 3

[3, 5, 6, 1, 20].indexOf(90)
// -> -1

// COMPATIBILITY CHANGE:
[0, false, 15].indexOf(false)
// Prototype 1.5 returns 0 (because 0 == false)
// Prototype 1.6 returns 1 (because 0 !== false)

without

2006-12-06T20:51:00Z

without(value...) -> newArray

Produces a new version of the array that does not contain any of the specified values.

Example

[3, 5, 6, 1, 20].without(3)
// -> [5, 6, 1, 20]

[3, 5, 6, 1, 20].without(20, 6)
// -> [3, 5, 1]

flatten

2006-12-06T20:38:00Z

flatten() -> newArray

Returns a “flat” (one-dimensional) version of the array. Nested arrays are recursively injected “inline.” This can prove very useful when handling the results of a recursive collection algorithm, for instance.

Example

['frank', ['bob', 'lisa'], ['jill', ['tom', 'sally']]].flatten()
// -> ['frank', 'bob', 'lisa', 'jill', 'tom', 'sally']

compact

2006-12-06T20:33:00Z

compact() -> newArray

Returns a new version of the array, without any null/undefined values.

Example

['frank', , 'sue', , 'sally', null].compact()
// -> ['frank', 'sue', 'sally']

last

2006-12-06T20:32:00Z

last() -> value

Returns the last item in the array, or undefined if the array is empty.

Example

['Ruby', 'Php', 'Python'].last()
// -> 'Python'

[].last()
// -> undefined

first

2006-12-06T20:30:00Z

first() -> value

Returns the first item in the array, or undefined if the array is empty.

Example

['Ruby', 'Php', 'Python'].first()
// -> 'Ruby'

[].first()
// -> undefined