JS: Function Object

By Xah Lee. Date: . Last updated: .

Function is the value of the property key "Function" of the global object. [JS: the Global Object]

console.log( window["Function"] === Function ); // true

Type

Function is a function.

[see JS: Value Types]

// type of Function
console.log ( typeof Function === "function" ); // true

Parent

Parent of Function is Function.prototype. [see JS: Prototype and Inheritance]

// parent of Function
console.log ( Object.getPrototypeOf ( Function ) === Function.prototype ); // true

Purpose

Purpose of Function is:

  1. To define a function from strings. (Useful when you need to generate function definition at run time).
  2. Holds the property key "prototype". The value of Function.prototype is the parent object of all function objects.

Function Constructor

JS: Function Constructor

Properties

Function.length

This is a data property. Its value is 1. This property has the attributes { writable: false, "enumerable": false, configurable: true }.

[see JS: Property Attributes, writable, enumerable, configurable]

ECMAScript 2015 §Fundamental Objects#sec-function.length

Reference

ECMAScript 2015 §Fundamental Objects#sec-function-objects

JS Function

  1. Define Function
  2. Arrow Function ⭐
  3. Function Params
  4. “arguments” Object
  5. Rest Params ⭐
  6. Arg Default Value ⭐
  7. Arg Destructure ⭐
  8. f Declaration vs Expression
  9. Closure
  10. f call apply bind
  11. Functional Programing
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