Arrayfrom

Array.from is a static method of the Array object in JavaScript. It creates a new array from an array-like or iterable object. It accepts two optional parameters: mapFn and thisArg.

If the first argument is a string, an arguments object, a NodeList, or any object with a length property and indexed elements, a new array is produced with the corresponding elements. If the first argument is iterable (implements Symbol.iterator), its elements are iterated to fill the array. This makes Array.from capable of converting both traditional array-like structures and modern iterables into real arrays.

If a mapFn is provided, it is called for each element with arguments (value, index, array) and its return value is used to populate the new array. If thisArg is supplied, it will be used as the this value when invoking mapFn. This enables customized transformations during the conversion process.

Examples:

- Array.from('hello') yields ['h','e','l','l','o'].

- Array.from({length: 3}, (_, i) => i) yields [0, 1, 2].

- Array.from(document.querySelectorAll('div')) yields an array of the selected elements (in environments with a DOM).

If the provided object is neither iterable nor array-like, Array.from throws a TypeError. It is widely supported in modern browsers and Node.js; older environments can use a polyfill. In practice, Array.from complements the spread operator and provides a single, consistent API for creating arrays from diverse inputs.