feat: add precision option to toHuman()

BREAKING CHANGES: `toHumman(timeUnit)` -> `toHuman({ timeUnit })`

Author: fent

README.md

@@ -55,13 +55,14 @@ Curent speed.
 ### StreamSpeed#avg
 Current average speed.
 
-### StreamSpeed.toHuman(bytes, timeUnit)
+### StreamSpeed.toHuman(bytes, options)
 Convenient method to convert `bytes` to a human readable string.
 
 ```js
-StreamSpeed.toHuman(1500); // 1.46KB
-StreamSpeed.toHuman(1024 * 1024); // 1MB
-StreamSpeed.toHuman(1024 * 1024 * 20.5, 's'); // 20.5MB/s
+StreamSpeed.toHuman(1500);                                  // 1.46KB
+StreamSpeed.toHuman(1024 * 1024);                           // 1MB
+StreamSpeed.toHuman(1024 * 1024 * 20.5, { timeUnit: 's' }); // 20.5MB/s
+StreamSpeed.toHuman(1024 * 1024 * 20.5, { precision: 3 });   // 20.50MB
 ```
 
 ### Event: 'speed'

lib/index.js

@@ -9,7 +9,7 @@ module.exports = class StreamSpeed extends EventEmitter {
    *
    * @constructor
    * @extends {EventEmitter}
-   * @param {number} per The time unit speed will be measured in.
+   * @param {number?} per The time unit speed will be measured in.
    */
   constructor(per) {
     super();
@@ -121,14 +121,18 @@ module.exports = class StreamSpeed extends EventEmitter {
    * Thank you Amir from StackOverflow.
    *
    * @param {number} bytes
+   * @param {Object} options
+   *  {string} timeUnit
+   *  {number?} precision
    * @return {string}
    */
-  static toHuman(bytes, timeUnit) {
+  static toHuman(bytes, options = {}) {
     const units = ' KMGTPEZYXWVU';
     if (bytes <= 0) { return '0'; }
-    timeUnit = timeUnit ? '/' + timeUnit : '';
+    options.timeUnit = options.timeUnit ? '/' + options.timeUnit : '';
     const t2 = Math.min(Math.floor(Math.log(bytes) / Math.log(1024)), 12);
-    return (Math.round(bytes * 100 / Math.pow(1024, t2)) / 100) +
-            units.charAt(t2).replace(' ', '') + 'B' + timeUnit;
+    let rate = Math.round(bytes * 100 / Math.pow(1024, t2)) / 100;
+    rate = options.precision ? rate.toPrecision(options.precision) : rate;
+    return rate + units.charAt(t2).replace(' ', '') + 'B' + options.timeUnit;
   }
 };

test/util-test.js

@@ -8,12 +8,29 @@ describe('StreamSpeed.toHuman()', () => {
   });
 
   it('Turns bytes into human readable size', () => {
-    assert.equal(StreamSpeed.toHuman(1024, 's'), '1KB/s');
-    assert.equal(StreamSpeed.toHuman(1024 * 1024 * 1.5, 's'), '1.5MB/s');
-  });
-
-  it('Turns bytes into human readable size (no time unit)', () => {
     assert.equal(StreamSpeed.toHuman(1024), '1KB');
     assert.equal(StreamSpeed.toHuman(1024 * 1024 * 1.5), '1.5MB');
   });
+
+  describe('With `timeUnit`', () => {
+    it('Turns bytes into human readable size', () => {
+      assert.equal(StreamSpeed.toHuman(1024, {
+        timeUnit: 's'
+      }), '1KB/s');
+      assert.equal(StreamSpeed.toHuman(1024 * 1024 * 1.5, {
+        timeUnit: 's'
+      }), '1.5MB/s');
+    });
+  });
+
+  describe('With `precision`', () => {
+    it('Formats speed with requested number of precision', () => {
+      assert.equal(StreamSpeed.toHuman(1024 * 1024 * 1.5, {
+        precision: 3
+      }), '1.50MB');
+      assert.equal(StreamSpeed.toHuman(1024 * 1024 * 1.1234567, {
+        precision: 2
+      }), '1.1MB');
+    });
+  });
 });