TypedArray.prototype.some()

The some() method tests whether some element in the typed array passes the test implemented by the provided function. This method has the same algorithm as Array.prototype.some(). TypedArray is one of the typed array types here.

Syntax

typedarray.some(callback[, thisArg])

Parameters

callback

Function to test for each element, taking three arguments:

currentValue

The current element being processed in the typed array.

index

The index of the current element being processed in the typed array.

array

The typed array every was called upon.

thisArg

Optional. Value to use as this when executing callback.

Return value

true if the callback function returns a truthy value for any array element; otherwise, false.

Description

The some method executes the callback function once for each element present in the typed array until it finds one where callback returns a true value. If such an element is found, some immediately returns true. Otherwise, some returns false.

callback is invoked with three arguments: the value of the element, the index of the element, and the array object being traversed.

If a thisArg parameter is provided to some, it will be passed to callback when invoked, for use as its this value. Otherwise, the value undefined will be passed for use as its this value.  The this value ultimately observable by callback is determined according to the usual rules for determining the this seen by a function.

some does not mutate the typed array on which it is called.

Examples

Testing size of all typed array elements

The following example tests whether any element in the typed array is bigger than 10.

function isBiggerThan10(element, index, array) {
  return element > 10;
}
new Uint8Array([2, 5, 8, 1, 4]).some(isBiggerThan10); // false
new Uint8Array([12, 5, 8, 1, 4]).some(isBiggerThan10); // true

Testing typed array elements using arrow functions

Arrow functions provide a shorter syntax for the same test.

new Uint8Array([2, 5, 8, 1, 4]).some(elem => elem > 10); // false
new Uint8Array([12, 5, 8, 1, 4]).some(elem => elem > 10); // true

Polyfill

Since there is no global object with the name TypedArray, polyfilling must be done on an "as needed" basis.

// https://tc39.github.io/ecma262/#sec-%typedarray%.prototype.some
if (!Uint8Array.prototype.some) {
  Object.defineProperty(Uint8Array.prototype, 'some', {
    value: Array.prototype.some
  });
}

If you need to support truly obsolete JavaScript engines that don't support Object.defineProperty, it's best not to polyfill Array.prototype methods at all, as you can't make them non-enumerable.

Specifications

Browser compatibility

See also

• TypedArray.prototype.every()
• Array.prototype.some()