[[MDN - Statements and declarations ]](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Statements) ---- [TOC] ---- ## `for...of` The **`for...of` statement** creates a loop iterating over [iterable objects](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Iteration_protocols#The_iterable_protocol), including: built-in `String`, `Array` array-like objects (e.g., [`arguments`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Functions/arguments "arguments is an Array-like object accessible inside functions that contains the values of the arguments passed to that function.") or [`NodeList`](https://developer.mozilla.org/en-US/docs/Web/API/NodeList "NodeList objects are collections of nodes, usually returned by properties such as Node.childNodes and methods such as document.querySelectorAll().")), [`TypedArray`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/TypedArray "A TypedArray object describes an array-like view of an underlying binary data buffer. There is no global property named TypedArray, nor is there a directly visible TypedArray constructor.  Instead, there are a number of different global properties, whose values are typed array constructors for specific element types, listed below. On the following pages you will find common properties and methods that can be used with any typed array containing elements of any type."), [`Map`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Map "The Map object holds key-value pairs and remembers the original insertion order of the keys."), [`Set`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Set "The Set object lets you store unique values of any type, whether primitive values or object references."), and user-defined iterables. It invokes a custom iteration hook with statements to be executed for the value of each distinct property of the object. ## `for...in` The **`for...in`** statement iterates over all non-[Symbol](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Symbol), [enumerable properties](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Enumerability_and_ownership_of_properties) of an object, in an arbitrary order. The `for...of` statement iterates over values that the [iterable object](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Guide/Iterators_and_Generators#Iterables) defines to be iterated over. ## `for await...of` The **`for await...of` statement** creates a loop iterating over async iterable objects as well as on sync iterables, including: built-in [`String`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String "The String global object is a constructor for strings or a sequence of characters."), [`Array`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array "The JavaScript Array object is a global object that is used in the construction of arrays; which are high-level, list-like objects."), `Array`\-like objects (e.g., [`arguments`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Functions/arguments "arguments is an Array-like object accessible inside functions that contains the values of the arguments passed to that function.") or [`NodeList`](https://developer.mozilla.org/en-US/docs/Web/API/NodeList "NodeList objects are collections of nodes, usually returned by properties such as Node.childNodes and methods such as document.querySelectorAll().")), [`TypedArray`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/TypedArray "A TypedArray object describes an array-like view of an underlying binary data buffer. There is no global property named TypedArray, nor is there a directly visible TypedArray constructor.  Instead, there are a number of different global properties, whose values are typed array constructors for specific element types, listed below. On the following pages you will find common properties and methods that can be used with any typed array containing elements of any type."), [`Map`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Map "The Map object holds key-value pairs and remembers the original insertion order of the keys."), [`Set`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Set "The Set object lets you store unique values of any type, whether primitive values or object references."), and user-defined async/sync iterables. It invokes a custom iteration hook with statements to be executed for the value of each distinct property of the object. ## `Map` The **`Map`** object holds key-value pairs and remembers the original insertion order of the keys. Any value (both objects and [primitive values](https://developer.mozilla.org/en-US/docs/Glossary/Primitive "primitive values: In JavaScript, a primitive (primitive value, primitive data type) is data that is not an object and has no methods. There are 7 primitive data types: string, number, bigint, boolean, null, undefined, and symbol.")) may be used as either a key or a value. A `Map` object iterates its elements in insertion order — a [`for...of`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Statements/for...of "The for...of statement creates a loop iterating over iterable objects, including: built-in String, Array, array-like objects (e.g., arguments or NodeList), TypedArray, Map, Set, and user-defined iterables. It invokes a custom iteration hook with statements to be executed for the value of each distinct property of the object.") loop returns an array of `[key, value]` for each iteration.