added reverse fill option

Author: Dipak Sarkar

src/number-format.js

@@ -9,7 +9,7 @@ export default function NumberFormat(opt = options) {
   this.input = ''
   this.number = ''
   this.isClean = false
-  this.isNull = (input = this.input) => !input.toString().replace(new RegExp('[^0-9]+', 'gi'), '')
+  this.isNull = (input = this.input) => !this.numberOnly(input, new RegExp('[^0-9]+', 'gi'))
   this.clean = (clean = false) => {
     this.isClean = clean
     return this
@@ -18,16 +18,32 @@ export default function NumberFormat(opt = options) {
     const sign = (this.input.toString().indexOf('-') >= 0 && this.realNumber() > 0) ? '-' : ''
     return sign
   }
+  function between(min, n, max) {
+    return Math.max(min, Math.min(n, max))
+  }
+  // Uncaught RangeError: toFixed() digits argument must be between 0 and 20 at Number.toFixed
+  function fixed(precision) {
+    return between(0, precision, 20)
+  }
+  function toFixed(numbers, precision) {
+    // eslint-disable-next-line no-restricted-properties
+    var exp = Math.pow(10, precision)
+    var float = parseFloat(numbers) / exp
+    return float.toFixed(fixed(precision))
+  }
   this.toNumber = (string) => Number(string)
+  this.numberOnly = (string, regExp) => string.toString().replace(regExp, '')
   this.isNegative = this.sign() === '-'
   this.numbers = () => {
-    if (typeof this.input === 'number') {
+    if (this.options.reverseFill) {
+      this.number = toFixed(this.numberOnly(this.input, /\D+/g), this.options.precision).replace('.', this.options.decimal)
+    } else if (typeof this.input === 'number') {
       this.number = this.toNumber(this.input.toFixed(this.options.precision)).toString().replace('-', '').replace('.', this.options.decimal)
     // eslint-disable-next-line no-restricted-globals
     } else if (!isNaN(this.toNumber(this.input))) {
       this.number = this.input.replace('-', '').replace('.', this.options.decimal)
     } else {
-      this.number = this.input.toString().replace(new RegExp(`[^0-9\\${this.options.decimal}]+`, 'gi'), '')
+      this.number = this.numberOnly(this.input, new RegExp(`[^0-9\\${this.options.decimal}]+`, 'gi'))
       this.number = this.parts(this.number).join(this.options.decimal)
     }
     return this.number

src/options.js

@@ -5,7 +5,7 @@ export default {
   decimal: '.',
   precision: 2,
   prefill: true,
-  reverse: false,
+  reverseFill: false,
   min: false,
   max: false,
   null_value: ''

tests/unit/number-format.reverse-fill.spec.js

@@ -0,0 +1,21 @@
+import NumberFormat from '../../src/number-format'
+
+describe('when enabled reverse fill', () => {
+  const numberFormat = new NumberFormat({
+    reverseFill: true
+  })
+  it('should return as follows', () => {
+    expect(numberFormat.format('sdfgasd55468.546')).toEqual('554,685.46')
+    expect(numberFormat.format('sdfgasd55468.546')).toEqual('554,685.46')
+    expect(numberFormat.format('sdfgasd55468.546-')).toEqual('-554,685.46')
+    expect(numberFormat.format('-1234.6512')).toEqual('-123,465.12')
+  })
+  it('should return as follows', () => {
+    expect(numberFormat.unformat('sdfgasd55468.546')).toEqual(554685.46)
+    expect(numberFormat.unformat('sdfgasd55468.546')).toEqual(554685.46)
+    expect(numberFormat.unformat('sdfgasd55468.546-')).toEqual(-554685.46)
+    expect(numberFormat.unformat('-1234.6512')).toEqual(-123465.12)
+  })
+})
+
+