Every

Check that all elements in array satisfy a condition.

• Array.prototype.every()

The every method executes the provided callback function once for each element present in the array until it finds the one where callback returns a falsy value. If such an element is found, the every method immediately returns false. Otherwise, if callback returns a truthy value for all elements, every returns true.

Caution: Calling this method on an empty array will return true for any condition!

Syntax

Pass a function, that takes 1 to 3 arguments.

every((element) => { ... } )
every((element, index) => { ... } )
every((element, index, array) => { ... } )

Or passing a callback function and optional success value instead of true.

every(callbackFn)
every(callbackFn, thisArg)

If a thisArg parameter is provided to every, it will be used as callback’s this value. Otherwise, the value undefined will be used as its this value.

Examples

Check all values are true.

[true, true, true].every(i => i === true)
// true

Check values all are positive.

[2, 3, 4].every(i => i > 0)
// true

Check values are equal.

const myArray = [2, 2, 2]

myArray.every(i => i === myArray[0])
// true

Other languages

Similar to all in Python.