Array.prototype.map()

The map() method of Array instances creates a new array populated with the results of calling a provided function on every element in the calling array.

The map() method is an iterative method. It calls a provided callbackFn function once for each element in an array and constructs a new array from the results.

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

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

Since map builds a new array, calling it without using the returned array is an anti-pattern; use forEach or for…of instead.

Syntax example: map(callbackFn)