feat($parse): Allow user-defined literals

src/ng/parse.js

@@ -463,8 +463,10 @@ AST.prototype = {
       primary = this.arrayDeclaration();
     } else if (this.expect('{')) {
       primary = this.object();
-    } else if (this.constants.hasOwnProperty(this.peek().text)) {
-      primary = copy(this.constants[this.consume().text]);
+    } else if (this.selfReferential.hasOwnProperty(this.peek().text)) {
+      primary = copy(this.selfReferential[this.consume().text]);
+    } else if (this.options.literals.hasOwnProperty(this.peek().text)) {
+      primary = { type: AST.Literal, value: this.options.literals[this.consume().text]};
     } else if (this.peek().identifier) {
       primary = this.identifier();
     } else if (this.peek().constant) {
@@ -616,15 +618,7 @@ AST.prototype = {
     return false;
   },
 
-
-  /* `undefined` is not a constant, it is an identifier,
-   * but using it as an identifier is not supported
-   */
-  constants: {
-    'true': { type: AST.Literal, value: true },
-    'false': { type: AST.Literal, value: false },
-    'null': { type: AST.Literal, value: null },
-    'undefined': {type: AST.Literal, value: undefined },
+  selfReferential: {
     'this': {type: AST.ThisExpression },
     '$locals': {type: AST.LocalsExpression }
   }
@@ -1669,7 +1663,7 @@ var Parser = function(lexer, $filter, options) {
   this.lexer = lexer;
   this.$filter = $filter;
   this.options = options;
-  this.ast = new AST(this.lexer);
+  this.ast = new AST(lexer, options);
   this.astCompiler = options.csp ? new ASTInterpreter(this.ast, $filter) :
                                    new ASTCompiler(this.ast, $filter);
 };
@@ -1746,16 +1740,39 @@ function getValueOf(value) {
 function $ParseProvider() {
   var cacheDefault = createMap();
   var cacheExpensive = createMap();
+  var literals = {
+    'true': true,
+    'false': false,
+    'null': null,
+    'undefined': undefined
+  };
+
+  /**
+   * @ngdoc method
+   * @name $parseProvider#addLiteral
+   * @description
+   *
+   * Configure $parse service to add literal values that will be present as literal at expressions.
+   *
+   * @param {string} literalName Token for the literal value. The literal name value must be a valid literal name.
+   * @param {*} literalValue Value for this literal. All literal values must be primitives or `undefined`.
+   *
+   **/
+  this.addLiteral = function(literalName, literalValue) {
+    literals[literalName] = literalValue;
+  };
 
   this.$get = ['$filter', function($filter) {
     var noUnsafeEval = csp().noUnsafeEval;
     var $parseOptions = {
           csp: noUnsafeEval,
-          expensiveChecks: false
+          expensiveChecks: false,
+          literals: copy(literals)
         },
         $parseOptionsExpensive = {
           csp: noUnsafeEval,
-          expensiveChecks: true
+          expensiveChecks: true,
+          literals: copy(literals)
         };
     var runningChecksEnabled = false;
 

test/ng/parseSpec.js

@@ -223,7 +223,7 @@ describe('parser', function() {
       /* global AST: false */
       createAst = function() {
         var lexer = new Lexer({csp: false});
-        var ast = new AST(lexer, {csp: false});
+        var ast = new AST(lexer, {csp: false, literals: {'true': true, 'false': false, 'undefined': undefined, 'null': null}});
         return ast.ast.apply(ast, arguments);
       };
     });
@@ -1681,6 +1681,19 @@ describe('parser', function() {
     $filterProvider = filterProvider;
   }]));
 
+  forEach([true, false], function(cspEnabled) {
+    beforeEach(module(['$parseProvider', function(parseProvider) {
+      parseProvider.addLiteral('Infinity', Infinity);
+    }]));
+
+    it('should allow extending literals with csp ' + cspEnabled, inject(function($rootScope) {
+      expect($rootScope.$eval("Infinity")).toEqual(Infinity);
+      expect($rootScope.$eval("-Infinity")).toEqual(-Infinity);
+      expect(function() {$rootScope.$eval("Infinity = 1");}).toThrow();
+      expect($rootScope.$eval("Infinity")).toEqual(Infinity);
+    }));
+  });
+
   forEach([true, false], function(cspEnabled) {
     describe('csp: ' + cspEnabled, function() {