feat($parse): allow strict equality in angular expressions

Allows the parser to parse strict equality and inequality
in angular expressions.

Closes #908

Author: jtymes

src/ng/parse.js

@@ -20,6 +20,8 @@ var OPERATORS = {
     '%':function(self, locals, a,b){return a(self, locals)%b(self, locals);},
     '^':function(self, locals, a,b){return a(self, locals)^b(self, locals);},
     '=':noop,
+    '===':function(self, locals, a, b){return a(self, locals)===b(self, locals);},
+    '!==':function(self, locals, a, b){return a(self, locals)!==b(self, locals);},
     '==':function(self, locals, a,b){return a(self, locals)==b(self, locals);},
     '!=':function(self, locals, a,b){return a(self, locals)!=b(self, locals);},
     '<':function(self, locals, a,b){return a(self, locals)<b(self, locals);},
@@ -70,9 +72,14 @@ function lex(text, csp){
       continue;
     } else {
       var ch2 = ch + peek(),
+          ch3 = ch2 + peek(2),
           fn = OPERATORS[ch],
-          fn2 = OPERATORS[ch2];
-      if (fn2) {
+          fn2 = OPERATORS[ch2],
+          fn3 = OPERATORS[ch3];
+      if (fn3) {
+        tokens.push({index:index, text:ch3, fn:fn3});
+        index += 3;
+      } else if (fn2) {
         tokens.push({index:index, text:ch2, fn:fn2});
         index += 2;
       } else if (fn) {
@@ -94,8 +101,9 @@ function lex(text, csp){
     return chars.indexOf(lastCh) != -1;
   }
 
-  function peek() {
-    return index + 1 < text.length ? text.charAt(index + 1) : false;
+  function peek(i) {
+    var num = i || 1;
+    return index + num < text.length ? text.charAt(index + num) : false;
   }
   function isNumber(ch) {
     return '0' <= ch && ch <= '9';
@@ -456,7 +464,7 @@ function parser(text, json, $filter, csp){
   function equality() {
     var left = relational();
     var token;
-    if ((token = expect('==','!='))) {
+    if ((token = expect('==','!=','===','!=='))) {
       left = binaryFn(left, token.fn, equality());
     }
     return left;

test/ng/parseSpec.js

@@ -91,15 +91,17 @@ describe('parser', function() {
       expect(tokens[1].text).toEqual('b');
     });
 
-    it('should tokenize relation', function() {
-      var tokens = lex("! == != < > <= >=");
+    it('should tokenize relation and equality', function() {
+      var tokens = lex("! == != < > <= >= === !==");
       expect(tokens[0].text).toEqual('!');
       expect(tokens[1].text).toEqual('==');
       expect(tokens[2].text).toEqual('!=');
       expect(tokens[3].text).toEqual('<');
       expect(tokens[4].text).toEqual('>');
       expect(tokens[5].text).toEqual('<=');
       expect(tokens[6].text).toEqual('>=');
+      expect(tokens[7].text).toEqual('===');
+      expect(tokens[8].text).toEqual('!==');
     });
 
     it('should tokenize statements', function() {
@@ -197,12 +199,20 @@ describe('parser', function() {
         expect(scope.$eval("false")).toBeFalsy();
         expect(scope.$eval("!true")).toBeFalsy();
         expect(scope.$eval("1==1")).toBeTruthy();
+        expect(scope.$eval("1==true")).toBeTruthy();
+        expect(scope.$eval("1===1")).toBeTruthy();
+        expect(scope.$eval("1==='1'")).toBeFalsy();
+        expect(scope.$eval("1===true")).toBeFalsy();
+        expect(scope.$eval("'true'===true")).toBeFalsy();
+        expect(scope.$eval("1!==2")).toBeTruthy();
+        expect(scope.$eval("1!=='1'")).toBeTruthy();
         expect(scope.$eval("1!=2")).toBeTruthy();
         expect(scope.$eval("1<2")).toBeTruthy();
         expect(scope.$eval("1<=1")).toBeTruthy();
         expect(scope.$eval("1>2")).toEqual(1>2);
         expect(scope.$eval("2>=1")).toEqual(2>=1);
-        expect(scope.$eval("true==2<3")).toEqual(true === 2<3);
+        expect(scope.$eval("true==2<3")).toEqual(true == 2<3);
+        expect(scope.$eval("true===2<3")).toEqual(true === 2<3);
       });
 
       it('should parse logical', function() {