ConvertANumberToHexadecimal.js

// Source : https://leetcode.com/problems/convert-a-number-to-hexadecimal
// Author : Dean Shi
// Date   : 2017-09-09

/***************************************************************************************
 *
 * Given an integer, write an algorithm to convert it to hexadecimal. For negative
 * integer, two’s complement method is used.
 *
 * Note:
 *
 * All letters in hexadecimal (a-f) must be in lowercase.
 * The hexadecimal string must not contain extra leading 0s. If the number is zero, it
 * is represented by a single zero character '0'; otherwise, the first character in the
 * hexadecimal string will not be the zero character.
 * The given number is guaranteed to fit within the range of a 32-bit signed integer.
 * You must not use any method provided by the library which converts/formats the
 * number to hex directly.
 *
 * Example 1:
 *
 * Input:
 * 26
 *
 * Output:
 * "1a"
 *
 * Example 2:
 *
 * Input:
 * -1
 *
 * Output:
 * "ffffffff"
 *
 *
 ***************************************************************************************/

/**
 * @param {number} num
 * @return {string}
 */
var toHex = function(num) {
    const hex = '0123456789abcdef'
    let rest, result = ''

    do {
        result = hex[num & 15] + result
    } while (num >>>= 4)

    return result
};