JavaScript: Array.prototype.some
arrayX.some(f)
-
Return
true
if the function f returntrue
for at least one element.As soon as f return
true
, exit the iteration and returntrue
.If array is empty, return false.
arrayX can be Array-Like Object.
The function f is passed 3 args:
- currentElement
- currentIndex
- arrayX
const ff = ((x) => (x === 3)); console.log([1, 2, 3, 4, 5, 6].some(ff) === 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) => { console.log(x); return x === 3; }); [1, 2, 3, 4, 5, 6].some(ff); /* prints 1 2 3 */
method 「some」 on Empty Array
some
on empty array returns false
.
console.log([].some((x) => true) === false);