Array.prototype.every()

The every() method of Array instances returns false if it finds an element in the array that does not satisfy the provided testing function. Otherwise, it returns true.

The every() method is an iterative method. It calls a provided callbackFn function once for each element in an array, until the callbackFn returns a falsy value. If such an element is found, every() immediately returns false and stops iterating through the array. Otherwise, if callbackFn returns a truthy value for all elements, every() returns true.

every acts like the “for all” quantifier in mathematics. In particular, for an empty array, it returns true. (It is vacuously true that all elements of the empty set satisfy any given condition.)

Syntax example: every(callbackFn)