You can instantiate Uint16Array from Uint8Array buffer value:

const uint8Array = new Uint8Array([1, 164, 5, 57])
const uint16Array = new Uint16Array(uint8Array.buffer)
// Uint16Array(2) [ 41985, 14597 ]

Uint***Arrays construct non-typed arrays (commented by @zfor, so, for example, push would be undefined) with numbers only (still bytes). The difference is that each constructor array has different byte range in memory. Uint8Array has 1 byte only, then the limit of a number is 255. Uint16Array is 2 bytes long, then the limit is 65535. Uint32Array is 4 bytes long, so the limit is 4294967295.

When constructing a Uint*Array you declare the array length as the first argument:

var arr = new Uint8Array(1);

If you declare a array/buffer/object instead, the constructor still proccess them as a Uint*Array.

var arr = new Uint8Array([10, 257]);
console.log(arr[0]); // 10
console.log(arr[1]); // 1 (same thing: 257 % 256)

Now, see some examples:

arr[0] = 256;
console.log(arr[0]); // 0

arr[0] = 255;
console.log(arr[0]); // 255

var t8 = new Uint8Array([1, 2, 3, 4]),
    t16 = new Uint16Array(t8);

That way the Uint16Array constructor will treat the t8 like an ordinary array (just like Uint8Array does the array literal) and will construct a new array (buffer) to which the elements are copied.

To create an ArrayBufferView on the same ArrayBuffer, you will need to pass that buffer into the constructor:

var t8=new Uint8Array([1, 2, 3, 4]),
    t16 = new Uint16Array( t8.buffer );
//                           ^^^^^^^
console.log(t16.byteLength/t16.length); // or: t16.constructor.BYTES_PER_ELEMENT
for (var i = 0; i < t16.length; i++)
    console.log(t16[i]);

You can use the buffer property, i.e. data_8 = new Uint8Array(data_16.buffer, data_16.byteOffset, data_16.byteLength).

You can use the buffer property, i.e. data_8 = new Uint8Array(data_16.buffer, data_16.byteOffset, data_16.byteLength).