From c7e5a4d5a3ff8ec67ad10c9169e785e915b9811f Mon Sep 17 00:00:00 2001
From: Martin Bayly <Martin.Bayly@D2L.com>
Date: Fri, 11 Mar 2016 11:04:15 -0800
Subject: [PATCH] added new method hasValueChanged to check to see if a new
 value would change the output value of the mask

---
 lib/index.js  |  7 +++++++
 test/index.js | 13 +++++++++++++
 2 files changed, 20 insertions(+)

diff --git a/lib/index.js b/lib/index.js
index 2427124..330cd5c 100644
--- a/lib/index.js
+++ b/lib/index.js
@@ -480,6 +480,13 @@ InputMask.prototype.getValue = function getValue() {
   return this.value.join('')
 }
 
+InputMask.prototype.hasValueChanged = function hasValueChanged(nextValue) {
+  if (!nextValue) {
+    nextValue = ''
+  }
+  return this.value.join('') !== this.pattern.formatValue(nextValue.split('')).join('')
+}
+
 InputMask.prototype.getRawValue = function getRawValue() {
   var rawValue = []
   for (var i = 0; i < this.value.length; i++) {
diff --git a/test/index.js b/test/index.js
index 1fee1df..8dd14ca 100644
--- a/test/index.js
+++ b/test/index.js
@@ -426,3 +426,16 @@ test('History', function(t) {
   t.deepEqual([mask.getValue(), mask.selection], ['abc123', {start: 6, end: 6}])
   t.false(mask.redo(), 'invalid redo - nothing more to redo')
 })
+
+test('hasValueChanged', function(t) {
+  t.plan(2)
+
+  function checkValueChanged(value, pattern, nextValue) {
+    var mask = new InputMask({pattern: pattern})
+    mask.paste(value)
+    return mask.hasValueChanged(nextValue)
+  }
+
+  t.true(checkValueChanged('100', '111%', '99'), 'value should have changed')
+  t.false(checkValueChanged('100', '111%', '100'), 'value should not have changed')
+})