tests, padding

index.js

@@ -50,10 +50,14 @@ function to_hex (str, encoding = '') {
  * encode a number to hex
  *
  * @param {number} n number to encode
+ * @param {number} padding minumum length of output
  * @returns {string} hex
  */
-function num_to_hex (n) {
-  return n.toString (16);
+function num_to_hex (n, padding = 0) {
+  const res = n.toString (16);
+  if (res.length < padding)
+    return '0'.repeat (padding - res.length) + res;
+  return res;
 }
 
 /**

test/index.js

@@ -6,6 +6,7 @@
  */
 
 // @ts-nocheck
+/* eslint-disable no-magic-numbers */
 'use strict';
 
 const test = require ('ava');
@@ -26,3 +27,23 @@ test ('encoding to_utf8', (t) => {
   const utf = encoding.to_utf8 ('Zm9v', 'base64');
   t.is (utf, 'foo');
 });
+
+test ('convert num to hex', (t) => {
+  const res = encoding.num_to_hex (11);
+  t.is (res, 'b');
+});
+
+test ('convert num to hex padded', (t) => {
+  const res = encoding.num_to_hex (11, 2);
+  t.is (res, '0b');
+});
+
+test ('convert hex to num', (t) => {
+  const res = encoding.hex_to_num ('b');
+  t.is (res, 11);
+});
+
+test ('convert hex padded to num', (t) => {
+  const res = encoding.hex_to_num ('0b');
+  t.is (res, 11);
+});