int16.js

/**
 * int16, and uint16 numbers in JS.
 *
 * by Dmitry Soshnikov <dmitry.soshnikov@gmail.com>
 */

const assert = require('assert');

/**
 * Converts a number to signed 16-bit integer.
 */
function int16(v) {
  return (v << 16) >> 16;
}

/**
 * Converts a number to unsigned 16-bit integer.
 */
function uint16(v) {
  return v & 0xFFFF;
}

// ------------------------------------------
// Tests

// int32
assert.equal(0xFFFF, 65535);
assert.equal(~0x0, -1);

// int16
assert.equal(int16(0xFFFF), -1);
assert.equal(int16(~0x0), -1);

// uint16
assert.equal(uint16(0xFFFF), 65535);
assert.equal(uint16(~0x0), 65535);

console.log('All tests passed!');