JS: Array.prototype.some

By Xah Lee. Date: . Last updated: .
Return true if the function f return true for at least one element.

As soon as f return true, exit the iteration and return true.

If array is empty, return false.

arrayX can be Array-Like Object.

The function f is passed 3 args:

  1. currentElement
  2. currentIndex
  3. arrayX
[1, 2, 3, 4, 5, 6].some(((x) => (x === 3))) === true
arrayX.some(f, thisArg)
Use thisArg for this Binding of f

Use “some” as Loop with Break

some is useful functional programing style of a loop that exit when a condition is met. (similar to forEach with break.)

Here is example. Apply f to each element in order. Exit the loop when f returns true.

const ff = ((x) => {
  return x === 3;

[1, 2, 3, 4, 5, 6].some(ff);


method 「some」 on Empty Array

some on empty array returns false.

[].some((x) => true) === false
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