TypedArray.prototype.slice()

start Optional

Zero-based index at which to begin extraction.

A negative index can be used, indicating an offset from the end of the sequence. slice(-2) extracts the last two elements in the sequence.

If start is undefined, slice begins from index 0.

end Optional

Zero-based index before which to end extraction. slice extracts up to but not including end.

For example, slice(1,4) extracts the second element through the fourth element (elements indexed 1, 2, and 3).

A negative index can be used, indicating an offset from the end of the sequence. slice(2,-1) extracts the third element through the second-to-last element in the sequence.

If end is omitted, slice extracts through the end of the sequence (typedarray.length).

A new typed array containing the extracted elements.

The slice method does not alter the original typed array, but instead returns a copy of a portion of the original typed array. As typed arrays only store primitive values, the copy the slice method returns is always a shallow copy.

If an element is changed in either typed array, the other typed array is not affected.

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

if (!Uint8Array.prototype.slice) {
  Object.defineProperty(Uint8Array.prototype, 'slice', {
    value: function (begin, end)
     {
        return new Uint8Array(Array.prototype.slice.call(this, begin, end));
     }
  });
}

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

• Polyfill of TypedArray.prototype.slice in core-js
• Array.prototype.slice()