refactor(*): introduce isNumberNaN

window.isNaN(‘lol’); //=> true
Number.isNaN(‘lol’); //=> false

isNaN converts it’s arguments into a Number before checking if it’s NaN.
In various places in the code base, we are checking if a variable is a Number and
NaN (or not), so this can be simplified with this new method (which is not exported on the
global Angular object).

Closes angular#11242

Author: PatrickJS

src/.eslintrc.json

@@ -45,6 +45,7 @@
     "isObject": false,
     "isString": false,
     "isNumber": false,
+    "isNumberNaN": false,
     "isDate": false,
     "isArray": false,
     "isFunction": false,

src/Angular.js

@@ -40,6 +40,7 @@
   isBlankObject,
   isString,
   isNumber,
+  isNumberNaN,
   isDate,
   isArray,
   isFunction,
@@ -413,6 +414,11 @@ function toInt(str) {
   return parseInt(str, 10);
 }
 
+var isNumberNaN = Number.isNaN || function isNumberNaN(num) {
+  // eslint-disable-next-line no-self-compare
+  return num !== num;
+};
+
 
 function inherit(parent, extra) {
   return extend(Object.create(parent), extra);
@@ -1277,7 +1283,7 @@ function timezoneToOffset(timezone, fallback) {
   // IE/Edge do not "understand" colon (`:`) in timezone
   timezone = timezone.replace(ALL_COLONS, '');
   var requestedTimezoneOffset = Date.parse('Jan 01, 1970 00:00:00 ' + timezone) / 60000;
-  return isNaN(requestedTimezoneOffset) ? fallback : requestedTimezoneOffset;
+  return isNumberNaN(requestedTimezoneOffset) ? fallback : requestedTimezoneOffset;
 }
 
 

src/ng/directive/input.js

@@ -1543,53 +1543,6 @@ function parseNumberAttrVal(val) {
   return !isNumberNaN(val) ? val : undefined;
 }
 
-function isNumberInteger(num) {
-  // See http://stackoverflow.com/questions/14636536/how-to-check-if-a-variable-is-an-integer-in-javascript#14794066
-  // (minus the assumption that `num` is a number)
-
-  // eslint-disable-next-line no-bitwise
-  return (num | 0) === num;
-}
-
-function countDecimals(num) {
-  var numString = num.toString();
-  var decimalSymbolIndex = numString.indexOf('.');
-
-  if (decimalSymbolIndex === -1) {
-    if (-1 < num && num < 1) {
-      // It may be in the exponential notation format (`1e-X`)
-      var match = /e-(\d+)$/.exec(numString);
-
-      if (match) {
-        return Number(match[1]);
-      }
-    }
-
-    return 0;
-  }
-
-  return numString.length - decimalSymbolIndex - 1;
-}
-
-function isValidForStep(viewValue, stepBase, step) {
-  // At this point `stepBase` and `step` are expected to be non-NaN values
-  // and `viewValue` is expected to be a valid stringified number.
-  var value = Number(viewValue);
-
-  // Due to limitations in Floating Point Arithmetic (e.g. `0.3 - 0.2 !== 0.1` or
-  // `0.5 % 0.1 !== 0`), we need to convert all numbers to integers.
-  if (!isNumberInteger(value) || !isNumberInteger(stepBase) || !isNumberInteger(step)) {
-    var decimalCount = Math.max(countDecimals(value), countDecimals(stepBase), countDecimals(step));
-    var multiplier = Math.pow(10, decimalCount);
-
-    value = value * multiplier;
-    stepBase = stepBase * multiplier;
-    step = step * multiplier;
-  }
-
-  return (value - stepBase) % step === 0;
-}
-
 function numberInputType(scope, element, attr, ctrl, $sniffer, $browser) {
   badInputChecker(scope, element, attr, ctrl);
   baseInputType(scope, element, attr, ctrl, $sniffer, $browser);

src/ng/directive/ngModel.js

@@ -548,7 +548,7 @@ var NgModelController = ['$scope', '$exceptionHandler', '$attrs', '$element', '$
    */
   this.$validate = function() {
     // ignore $validate before model is initialized
-    if (isNumber(ctrl.$modelValue) && isNaN(ctrl.$modelValue)) {
+    if (isNumberNaN(ctrl.$modelValue)) {
       return;
     }
 
@@ -719,7 +719,7 @@ var NgModelController = ['$scope', '$exceptionHandler', '$attrs', '$element', '$
         }
       }
     }
-    if (isNumber(ctrl.$modelValue) && isNaN(ctrl.$modelValue)) {
+    if (isNumberNaN(ctrl.$modelValue)) {
       // ctrl.$modelValue has not been touched yet...
       ctrl.$modelValue = ngModelGet($scope);
     }

src/ng/directive/ngPluralize.js

@@ -206,7 +206,7 @@ var ngPluralizeDirective = ['$locale', '$interpolate', '$log', function($locale,
 
       scope.$watch(numberExp, function ngPluralizeWatchAction(newVal) {
         var count = parseFloat(newVal);
-        var countIsNaN = isNaN(count);
+        var countIsNaN = isNumberNaN(count);
 
         if (!countIsNaN && !(count in whens)) {
           // If an explicit number rule such as 1, 2, 3... is defined, just use it.
@@ -216,7 +216,7 @@ var ngPluralizeDirective = ['$locale', '$interpolate', '$log', function($locale,
 
         // If both `count` and `lastCount` are NaN, we don't need to re-register a watch.
         // In JS `NaN !== NaN`, so we have to explicitly check.
-        if ((count !== lastCount) && !(countIsNaN && isNumber(lastCount) && isNaN(lastCount))) {
+        if ((count !== lastCount) && !(countIsNaN && isNumberNaN(lastCount))) {
           watchRemover();
           var whenExpFn = whensExpFns[count];
           if (isUndefined(whenExpFn)) {

src/ng/directive/validators.js

@@ -259,7 +259,7 @@ var maxlengthDirective = function() {
       var maxlength = -1;
       attr.$observe('maxlength', function(value) {
         var intVal = toInt(value);
-        maxlength = isNaN(intVal) ? -1 : intVal;
+        maxlength = isNumberNaN(intVal) ? -1 : intVal;
         ctrl.$validate();
       });
       ctrl.$validators.maxlength = function(modelValue, viewValue) {

src/ng/filter/limitTo.js

@@ -106,7 +106,7 @@ function limitToFilter() {
     } else {
       limit = toInt(limit);
     }
-    if (isNaN(limit)) return input;
+    if (isNumberNaN(limit)) return input;
 
     if (isNumber(input)) input = input.toString();
     if (!isArrayLike(input)) return input;

src/ng/rootScope.js

@@ -806,8 +806,7 @@ function $RootScopeProvider() {
                     if ((value = get(current)) !== (last = watch.last) &&
                         !(watch.eq
                             ? equals(value, last)
-                            : (typeof value === 'number' && typeof last === 'number'
-                               && isNaN(value) && isNaN(last)))) {
+                            : (isNumberNaN(value) && isNumberNaN(last)))) {
                       dirty = true;
                       lastDirtyWatch = watch;
                       watch.last = watch.eq ? copy(value, null) : value;

test/.eslintrc.json

@@ -59,6 +59,7 @@
     "isObject": false,
     "isString": false,
     "isNumber": false,
+    "isNumberNaN": false,
     "isDate": false,
     "isArray": false,
     "isFunction": false,

test/ng/directive/selectSpec.js

@@ -1223,6 +1223,5 @@ describe('select', function() {
                 '</select>');
       }).toThrowMinErr('ng','badname', 'hasOwnProperty is not a valid "option value" name');
     });
-
   });
 });