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Array.from is a static method of the JavaScript Array object. It creates a new Array instance from an array-like or iterable object. The method accepts three arguments: arrayLike, mapFn (optional), and thisArg (optional).

An array-like object is one that has a length property and indexed elements, such as the arguments object or a DOM NodeList. An iterable object includes strings, Sets, Maps, and other objects that implement the iterable protocol. When called, Array.from returns a new array containing the elements of the provided input in order. It can also convert certain non-array structures, such as a string, into an array of its characters.

If a mapFn is supplied, it is invoked for each element of the input, with the signature mapFn(value, index, object). The return value of mapFn is used as the corresponding element in the new array. An optional thisArg can be provided to set the this value inside mapFn.

Common uses include converting NodeLists or arguments to real arrays, turning a string into an array of characters, or turning a Set or Map into an array. For Maps, the resulting array contains [key, value] pairs unless a mapFn transforms them. Array.from does not mutate the original input; it produces a separate new array.

Support for Array.from is widespread in modern JavaScript environments (ES6 and later). In environments lacking native support, a polyfill can provide equivalent functionality.