JS: Array.prototype

What is Array.prototype

Purpose

Purpose of Array.prototype is to provide methods and properties useful for all array objects

Array.prototype is the parent of all array objects.

Type

interesting note

The Array prototype object is an Array exotic object …

Note: The Array prototype object is specified to be an Array exotic object to ensure compatibility with ECMAScript code that was created prior to the ECMAScript 2015 specification. Pre-ES2015 code (and some engines) treated Array.prototype as a real array. Making it a plain object would have broken existing programs, so the committee kept the exotic-array behavior.

Type of Array.prototype is Object .

console.assert(typeof Array.prototype === "object");

Array.prototype is a true array. Meaning, you can push elements to it, and with a magical length property.

console.assert((Array.isArray(Array.prototype)) === true);
console.assert(Array.prototype.length === 0);
Array.prototype.push("x");
console.assert(Array.prototype[0] === "x");
console.assert(Array.prototype.length === 1);

Properties

Value Properties

• JS: Array.prototype.length
• JS: Array.prototype.constructor

Function Properties

Get Set an element by index

• JS: Array.prototype.at
• JS: Array.prototype.with

Add, Remove

• JS: Array.prototype.pop
• JS: Array.prototype.push
• JS: Array.prototype.shift
• JS: Array.prototype.unshift

Add or Remove Subarray

• JS: Array.prototype.concat
• JS: Array.prototype.slice (extract)
• JS: Array.prototype.splice (remove and add at index)
• JS: Array.prototype.toSpliced (λ)

Sort, Reverse

• JS: Array.prototype.sort
• JS: Array.prototype.toSorted
• JS: Array.prototype.reverse
• JS: Array.prototype.toReversed

Map, Iteration, Reduce

• JS: Array.prototype.map
• JS: Array.prototype.flatMap
• JS: Array.prototype.forEach
• JS: Array.prototype.filter
• JS: Array.prototype.fill
• JS: Array.prototype.copyWithin
• JS: Array.prototype.some
• JS: Array.prototype.every
• JS: Array.prototype.reduce
• JS: Array.prototype.reduceRight
• JS: Array.prototype.flat

Find element

• JS: Array.prototype.includes

• JS: Array.prototype.indexOf
• JS: Array.prototype.lastIndexOf

• JS: Array.prototype.find
• JS: Array.prototype.findIndex

• JS: Array.prototype.findLast
• JS: Array.prototype.findLastIndex

Convert to string

• JS: Array.prototype.join (to string)
• JS: Array.toString

Array Iterator

• JS: Array.prototype.entries
• JS: Array.prototype.keys
• JS: Array.prototype.values

Other

• Array.prototype.toLocaleString
• Array.prototype[Symbol.iterator] (same as Array.prototype.values)
• Array.prototype[Symbol.unscopables]