/*
 * Decimal number to others
 */
let number = 31;
number.toString(2); //  "11111", To Binary string
number.toString(8); //  "37"   , To Octal string
number.toString(16); // "1F"   , To Hexadecimal string

/*
 * Others to Decimal
 *
 * After ECMAScript-2015, Number.parseInt === window.parseInt
 */
Number.parseInt("11111", 2); // 31,  Binary to Decimal
Number.parseInt("37", 8); //    31, Octal to Decimal
Number.parseInt("1f", 16); //   31, Hexadecimal to Decimal

/*
 * Get code of a Chinese character
 */
let c = "知"; // 30694 (Dec)
let code = c.charCodeAt().toString(8);  // 73745, 073745 === 30694 === 0x77e5

String.fromCharCode(Number.parseInt(73745, 8)); // "知"
Number.parseInt("FF", 16).toString(2);  // "11111111"


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