Array.prototype.forEach()

The forEach() method of Array instances executes a provided function once for each array element.

The forEach() method is an iterative method. It calls a provided callbackFn function once for each element in an array in ascending-index order. Unlike map(), forEach() always returns undefined and is not chainable. The typical use case is to execute side effects at the end of a chain.

callbackFn is invoked only for array indexes which have assigned values. It is not invoked for empty slots in sparse arrays.

The forEach() method is generic. It only expects the this value to have a length property and integer-keyed properties.

Syntax example: forEach(callbackFn)