[User Experience Improvement] for Number Field, if allowing decimal, …

…when the field is emtpy, the first "." will be considered as decimal input (text-mask#542)

.travis.yml

@@ -1,6 +1,7 @@
 language: node_js
 
-node_js: "node"
+node_js: 
+  - "7"
 
 install: true
 

addons/src/createNumberMask.js

@@ -34,6 +34,11 @@ export default function createNumberMask({
       (rawValue[0] === prefix[0] && rawValueLength === 1)
     ) {
       return prefix.split(emptyString).concat([digitRegExp]).concat(suffix.split(emptyString))
+    } else if(
+      rawValue === decimalSymbol &&
+      allowDecimal
+    ) {
+      return prefix.split(emptyString).concat(['0', decimalSymbol, digitRegExp]).concat(suffix.split(emptyString))
     }
 
     const indexOfLastDecimal = rawValue.lastIndexOf(decimalSymbol)

addons/test/createNumberMask.spec.js

@@ -102,6 +102,23 @@ describe('createNumberMask', () => {
     expect(numberMask('-')).to.deep.equal([/-/, '$', /\d/])
   })
 
+  it('starts with dot should be considered as decimal input', () => {
+    let numberMask = createNumberMask({prefix: '$', allowDecimal: true})
+    expect(numberMask('.')).to.deep.equal(['$', '0', '.', /\d/])
+
+    numberMask = createNumberMask({prefix: '#', allowDecimal: true})
+    expect(numberMask('.')).to.deep.equal(['#', '0', '.', /\d/])
+
+    numberMask = createNumberMask({prefix: '', allowDecimal: true})
+    expect(numberMask('.')).to.deep.equal(['0', '.', /\d/])
+
+    numberMask = createNumberMask({allowDecimal: false})
+    expect(numberMask('.')).to.deep.equal(['$'])
+
+    numberMask = createNumberMask({prefix: '', suffix: '$', allowDecimal: true})
+    expect(numberMask('.')).to.deep.equal(['0', '.', /\d/, '$'])
+  })
+
   it('can allow leading zeroes', function() {
     let numberMask = createNumberMask({allowLeadingZeroes: true})
     expect(numberMask('012')).to.deep.equal(['$', /\d/, /\d/, /\d/])