Added byteFormat to Localization

lib/Localization.js

@@ -645,6 +645,48 @@ module.exports = class Localization {
     )
   }
 
+  /**
+   * Byte format or factors of 1024
+   *
+   * @param { number } value          Value to format
+   * @param { number } precision      Number of decimals
+   * @param { string } unit           Unit
+   * @param { string } [power]        Force to the given power
+   * @return { string }               Value formatted in the powers of 1024
+   */
+  byteFormat (value, precision = 1, unit = 'B', power = null) {
+    if (isObject(precision)) {
+      const opts = precision
+      opts.precision = opts.precision != null ? opts.precision : 1
+      opts.unit = opts.unit != null ? opts.unit : unit
+      opts.power = opts.power != null ? opts.power : 1
+
+      return this.byteFormat(value, opts.precision, opts.unit, opts.power)
+    }
+
+    const units = ['', 'k', 'M', 'G', 'T', 'P']
+    let pow = 0
+
+    for (let i = 0; i < units.length; i++) {
+      const d = Math.pow(1024, i)
+
+      if (Math.round(value / d) < 1) {
+        break
+      }
+
+      pow = i
+    }
+
+    if (power && units.includes(power)) {
+      pow = units.indexOf(power)
+    }
+
+    const v = value / Math.pow(1024, pow)
+    const f = units[pow]
+
+    return `${this.numberFormat(v, precision)} ${f}${unit}`
+  }
+
   /**
    * Localized percent format. Gets the number from numberFormat and appends a
    * percent symbol to the return value.

package.json

@@ -1,6 +1,6 @@
 {
   "name": "helpers.js",
-  "version": "0.15.2",
+  "version": "0.16.0",
   "description": "Miscellaneous helpers",
   "main": "index.js",
   "scripts": {

tests/localization/byteFormat.js

@@ -0,0 +1,34 @@
+const expect = require('expect.js')
+const Localization = require('../../lib/Localization')
+
+describe('Localization byteFormat', () => {
+  const l10n = new Localization()
+
+  it('should output the given value appended with unit using the given precision', (done) => {
+    expect(l10n.byteFormat(20)).to.be('20.0 B')
+    expect(l10n.byteFormat(20, 2)).to.be('20.00 B')
+    done()
+  })
+
+  it('should output the given value appended with quantifier using the given precision', (done) => {
+    expect(l10n.byteFormat(1024, 0)).to.be('1 kB')
+    expect(l10n.byteFormat(1024 * 1024, 2)).to.be('1.00 MB')
+    expect(l10n.byteFormat(100 * 1024 * 1024, 2)).to.be('100.00 MB')
+    expect(l10n.byteFormat(256 * 1024 * 1024 * 1024, 0, 'Hz')).to.be('256 GHz')
+    done()
+  })
+
+  it('should override power when given', (done) => {
+    expect(l10n.byteFormat(100 * 1024, 3, 'B', 'M')).to.be('0.098 MB')
+    expect(l10n.byteFormat(100 * 1024 * 1024, 0, 'Hz', 'k')).to.be('102,400 kHz')
+    done()
+  })
+
+  it('should accept a configuration object for the parameters', (done) => {
+    expect(l10n.byteFormat(50, {})).to.be('50.0 B')
+    expect(l10n.byteFormat(50 * 1024, { power: 'k' })).to.be('50.0 kB')
+    expect(l10n.byteFormat(100 * 1024, { precision: 3, power: 'M' })).to.be('0.098 MB')
+    expect(l10n.byteFormat(100 * 1024 * 1024, { precision: 0, unit: 'Hz', power: 'k' })).to.be('102,400 kHz')
+    done()
+  })
+})