Throw error for reserved words enum and await (#195)

* Throw error for reserved words enum and await when source type is module

* Extract reserved word check into method

* Fix tests

src/parser/expression.js

@@ -827,13 +827,7 @@ pp.parseObjPropValue = function (prop, startPos, startLoc, isGenerator, isAsync,
 
   if (!prop.computed && prop.key.type === "Identifier") {
     if (isPattern) {
-      let illegalBinding = this.isKeyword(prop.key.name);
-      if (!illegalBinding && this.state.strict) {
-        illegalBinding = reservedWords.strictBind(prop.key.name) || reservedWords.strict(prop.key.name);
-      }
-      if (illegalBinding) {
-        this.raise(prop.key.start, "Binding " + prop.key.name);
-      }
+      this.checkReservedWord(prop.key.name, prop.key.start, true, true);
       prop.value = this.parseMaybeDefault(startPos, startLoc, prop.key.__clone());
     } else if (this.match(tt.eq) && refShorthandDefaultPos) {
       if (!refShorthandDefaultPos.start) {
@@ -843,6 +837,7 @@ pp.parseObjPropValue = function (prop, startPos, startLoc, isGenerator, isAsync,
     } else {
       prop.value = prop.key.__clone();
     }
+
     prop.shorthand = true;
     return this.finishNode(prop, "ObjectProperty");
   }
@@ -998,8 +993,8 @@ pp.parseIdentifier = function (liberal) {
   let node = this.startNode();
 
   if (this.match(tt.name)) {
-    if (!liberal && this.state.strict && reservedWords.strict(this.state.value)) {
-      this.raise(this.state.start, "The keyword '" + this.state.value + "' is reserved");
+    if (!liberal) {
+      this.checkReservedWord(this.state.value, this.state.start, false, false);
     }
 
     node.name = this.state.value;
@@ -1019,6 +1014,16 @@ pp.parseIdentifier = function (liberal) {
   return this.finishNode(node, "Identifier");
 };
 
+pp.checkReservedWord = function (word, startLoc, checkKeywords, isBinding) {
+  if (this.isReservedWord(word) || (checkKeywords && this.isKeyword(word))) {
+    this.raise(startLoc, word + " is a reserved word");
+  }
+
+  if (this.state.strict && (reservedWords.strict(word) || (isBinding && reservedWords.strictBind(word)))) {
+    this.raise(startLoc, word + " is a reserved word in strict mode");
+  }
+};
+
 // Parses await expression inside async function.
 
 pp.parseAwait = function (node) {

src/parser/index.js

@@ -11,7 +11,6 @@ export default class Parser extends Tokenizer {
 
     this.options = options;
     this.inModule = this.options.sourceType === "module";
-    this.isReservedWord = reservedWords[6];
     this.input = input;
     this.plugins = this.loadPlugins(this.options.plugins);
     this.filename = options.sourceFilename;
@@ -22,6 +21,14 @@ export default class Parser extends Tokenizer {
     }
   }
 
+  isReservedWord(word: string): boolean {
+    if (word === "await") {
+      return this.inModule;
+    } else {
+      return reservedWords[6](word);
+    }
+  }
+
   hasPlugin(name: string): boolean {
     return !!(this.plugins["*"] || this.plugins[name]);
   }

src/parser/lval.js

@@ -2,7 +2,6 @@
 
 import { types as tt } from "../tokenizer/types";
 import Parser from "./index";
-import { reservedWords } from "../util/identifier";
 
 const pp = Parser.prototype;
 
@@ -204,9 +203,7 @@ pp.parseMaybeDefault = function (startPos, startLoc, left) {
 pp.checkLVal = function (expr, isBinding, checkClashes, contextDescription) {
   switch (expr.type) {
     case "Identifier":
-      if (this.state.strict && (reservedWords.strictBind(expr.name) || reservedWords.strict(expr.name))) {
-        this.raise(expr.start, (isBinding ? "Binding " : "Assigning to ") + expr.name + " in strict mode");
-      }
+      this.checkReservedWord(expr.name, expr.start, false, true);
 
       if (checkClashes) {
         // we need to prefix this with an underscore for the cases where we have a key of