[[FEAT]] Implement support for ES8 trailing commas

jshint · Jul 24, 2018 · 94d7a7e · 94d7a7e
1 parent 7acea75
commit 94d7a7e
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Showing 4 changed files with 36 additions and 95 deletions.
diff --git a/src/jshint.js b/src/jshint.js
@@ -1071,12 +1071,11 @@ var JSHINT = (function() {
       case "}":
       case "]":
       case ",":
+      case ")":
         if (opts.allowTrailing) {
           return true;
         }
 
-        /* falls through */
-      case ")":
         error("E024", state.tokens.next, state.tokens.next.value);
         return false;
       }
@@ -3211,13 +3210,18 @@ var JSHINT = (function() {
 
       // now we have evaluated the default expression, add the variable to the param scope
       currentParams.forEach(addParam);
-
       if (state.tokens.next.id === ",") {
         if (pastRest) {
           warning("W131", state.tokens.next);
         }
-        parseComma();
-      } else {
+        parseComma({ allowTrailing: true });
+      }
+
+      if (state.tokens.next.id === ")") {
+        if (state.tokens.curr.id === "," && !state.inES8()) {
+          warning("W119", state.tokens.curr, "Trailing comma in function parameters", "8");
+        }
+
         advance(")", next);
         return {
           arity: arity,

diff --git a/src/state.js b/src/state.js
@@ -65,6 +65,15 @@ var state = {
     return this.option.moz;
   },
 
+  /**
+   * Determine if constructs introduced in ECMAScript 8 should be accepted.
+   *
+   * @returns {boolean}
+   */
+  inES8: function() {
+    return this.esVersion >= 8;
+  },
+
   /**
    * Determine if constructs introduced in ECMAScript 7 should be accepted.
    *

diff --git a/tests/test262/expectations.txt b/tests/test262/expectations.txt
@@ -2711,14 +2711,8 @@ test/language/expressions/generators/dflt-params-ref-later.js(default)
 test/language/expressions/generators/dflt-params-ref-later.js(strict mode)
 test/language/expressions/generators/dflt-params-ref-self.js(default)
 test/language/expressions/generators/dflt-params-ref-self.js(strict mode)
-test/language/expressions/generators/dflt-params-trailing-comma.js(default)
-test/language/expressions/generators/dflt-params-trailing-comma.js(strict mode)
 test/language/expressions/generators/named-yield-identifier-non-strict.js(default)
 test/language/expressions/generators/named-yield-identifier-spread-non-strict.js(default)
-test/language/expressions/generators/params-trailing-comma-multiple.js(default)
-test/language/expressions/generators/params-trailing-comma-multiple.js(strict mode)
-test/language/expressions/generators/params-trailing-comma-single.js(default)
-test/language/expressions/generators/params-trailing-comma-single.js(strict mode)
 test/language/expressions/generators/yield-identifier-non-strict.js(default)
 test/language/expressions/generators/yield-identifier-spread-non-strict.js(default)
 test/language/expressions/async-generator/args-trailing-comma-multiple.js(default)
@@ -3757,12 +3751,6 @@ test/language/expressions/function/dflt-params-ref-later.js(default)
 test/language/expressions/function/dflt-params-ref-later.js(strict mode)
 test/language/expressions/function/dflt-params-ref-self.js(default)
 test/language/expressions/function/dflt-params-ref-self.js(strict mode)
-test/language/expressions/function/dflt-params-trailing-comma.js(default)
-test/language/expressions/function/dflt-params-trailing-comma.js(strict mode)
-test/language/expressions/function/params-trailing-comma-multiple.js(default)
-test/language/expressions/function/params-trailing-comma-multiple.js(strict mode)
-test/language/expressions/function/params-trailing-comma-single.js(default)
-test/language/expressions/function/params-trailing-comma-single.js(strict mode)
 test/language/expressions/class/accessor-name-inst-computed-yield-expr.js(default)
 test/language/expressions/class/accessor-name-inst-computed-yield-expr.js(strict mode)
 test/language/expressions/class/accessor-name-inst-literal-string-unicode-escape.js(default)
@@ -4795,42 +4783,18 @@ test/language/expressions/class/gen-meth-dflt-params-ref-later.js(default)
 test/language/expressions/class/gen-meth-dflt-params-ref-later.js(strict mode)
 test/language/expressions/class/gen-meth-dflt-params-ref-self.js(default)
 test/language/expressions/class/gen-meth-dflt-params-ref-self.js(strict mode)
-test/language/expressions/class/gen-meth-dflt-params-trailing-comma.js(default)
-test/language/expressions/class/gen-meth-dflt-params-trailing-comma.js(strict mode)
-test/language/expressions/class/gen-meth-params-trailing-comma-multiple.js(default)
-test/language/expressions/class/gen-meth-params-trailing-comma-multiple.js(strict mode)
-test/language/expressions/class/gen-meth-params-trailing-comma-single.js(default)
-test/language/expressions/class/gen-meth-params-trailing-comma-single.js(strict mode)
 test/language/expressions/class/gen-meth-static-dflt-params-ref-later.js(default)
 test/language/expressions/class/gen-meth-static-dflt-params-ref-later.js(strict mode)
 test/language/expressions/class/gen-meth-static-dflt-params-ref-self.js(default)
 test/language/expressions/class/gen-meth-static-dflt-params-ref-self.js(strict mode)
-test/language/expressions/class/gen-meth-static-dflt-params-trailing-comma.js(default)
-test/language/expressions/class/gen-meth-static-dflt-params-trailing-comma.js(strict mode)
-test/language/expressions/class/gen-meth-static-params-trailing-comma-multiple.js(default)
-test/language/expressions/class/gen-meth-static-params-trailing-comma-multiple.js(strict mode)
-test/language/expressions/class/gen-meth-static-params-trailing-comma-single.js(default)
-test/language/expressions/class/gen-meth-static-params-trailing-comma-single.js(strict mode)
 test/language/expressions/class/meth-dflt-params-ref-later.js(default)
 test/language/expressions/class/meth-dflt-params-ref-later.js(strict mode)
 test/language/expressions/class/meth-dflt-params-ref-self.js(default)
 test/language/expressions/class/meth-dflt-params-ref-self.js(strict mode)
-test/language/expressions/class/meth-dflt-params-trailing-comma.js(default)
-test/language/expressions/class/meth-dflt-params-trailing-comma.js(strict mode)
-test/language/expressions/class/meth-params-trailing-comma-multiple.js(default)
-test/language/expressions/class/meth-params-trailing-comma-multiple.js(strict mode)
-test/language/expressions/class/meth-params-trailing-comma-single.js(default)
-test/language/expressions/class/meth-params-trailing-comma-single.js(strict mode)
 test/language/expressions/class/meth-static-dflt-params-ref-later.js(default)
 test/language/expressions/class/meth-static-dflt-params-ref-later.js(strict mode)
 test/language/expressions/class/meth-static-dflt-params-ref-self.js(default)
 test/language/expressions/class/meth-static-dflt-params-ref-self.js(strict mode)
-test/language/expressions/class/meth-static-dflt-params-trailing-comma.js(default)
-test/language/expressions/class/meth-static-dflt-params-trailing-comma.js(strict mode)
-test/language/expressions/class/meth-static-params-trailing-comma-multiple.js(default)
-test/language/expressions/class/meth-static-params-trailing-comma-multiple.js(strict mode)
-test/language/expressions/class/meth-static-params-trailing-comma-single.js(default)
-test/language/expressions/class/meth-static-params-trailing-comma-single.js(strict mode)
 test/language/expressions/object/accessor-name-computed-yield-expr.js(default)
 test/language/expressions/object/accessor-name-computed-yield-expr.js(strict mode)
 test/language/expressions/object/accessor-name-computed-yield-id.js(default)
@@ -5352,34 +5316,16 @@ test/language/expressions/object/method-definition/gen-meth-dflt-params-ref-late
 test/language/expressions/object/method-definition/gen-meth-dflt-params-ref-later.js(strict mode)
 test/language/expressions/object/method-definition/gen-meth-dflt-params-ref-self.js(default)
 test/language/expressions/object/method-definition/gen-meth-dflt-params-ref-self.js(strict mode)
-test/language/expressions/object/method-definition/gen-meth-dflt-params-trailing-comma.js(default)
-test/language/expressions/object/method-definition/gen-meth-dflt-params-trailing-comma.js(strict mode)
-test/language/expressions/object/method-definition/gen-meth-params-trailing-comma-multiple.js(default)
-test/language/expressions/object/method-definition/gen-meth-params-trailing-comma-multiple.js(strict mode)
-test/language/expressions/object/method-definition/gen-meth-params-trailing-comma-single.js(default)
-test/language/expressions/object/method-definition/gen-meth-params-trailing-comma-single.js(strict mode)
 test/language/expressions/object/method-definition/gen-yield-identifier-non-strict.js(default)
 test/language/expressions/object/method-definition/gen-yield-identifier-spread-non-strict.js(default)
 test/language/expressions/object/method-definition/meth-dflt-params-ref-later.js(default)
 test/language/expressions/object/method-definition/meth-dflt-params-ref-later.js(strict mode)
 test/language/expressions/object/method-definition/meth-dflt-params-ref-self.js(default)
 test/language/expressions/object/method-definition/meth-dflt-params-ref-self.js(strict mode)
-test/language/expressions/object/method-definition/meth-dflt-params-trailing-comma.js(default)
-test/language/expressions/object/method-definition/meth-dflt-params-trailing-comma.js(strict mode)
-test/language/expressions/object/method-definition/meth-params-trailing-comma-multiple.js(default)
-test/language/expressions/object/method-definition/meth-params-trailing-comma-multiple.js(strict mode)
-test/language/expressions/object/method-definition/meth-params-trailing-comma-single.js(default)
-test/language/expressions/object/method-definition/meth-params-trailing-comma-single.js(strict mode)
 test/language/expressions/arrow-function/dflt-params-ref-later.js(default)
 test/language/expressions/arrow-function/dflt-params-ref-later.js(strict mode)
 test/language/expressions/arrow-function/dflt-params-ref-self.js(default)
 test/language/expressions/arrow-function/dflt-params-ref-self.js(strict mode)
-test/language/expressions/arrow-function/dflt-params-trailing-comma.js(default)
-test/language/expressions/arrow-function/dflt-params-trailing-comma.js(strict mode)
-test/language/expressions/arrow-function/params-trailing-comma-single.js(default)
-test/language/expressions/arrow-function/params-trailing-comma-single.js(strict mode)
-test/language/expressions/arrow-function/params-trailing-comma-multiple.js(default)
-test/language/expressions/arrow-function/params-trailing-comma-multiple.js(strict mode)
 
 # Async iteration
 test/language/statements/for-await-of/async-func-dstr-const-ary-init-iter-close.js(default)
@@ -6137,22 +6083,10 @@ test/language/statements/function/dflt-params-ref-later.js(default)
 test/language/statements/function/dflt-params-ref-later.js(strict mode)
 test/language/statements/function/dflt-params-ref-self.js(default)
 test/language/statements/function/dflt-params-ref-self.js(strict mode)
-test/language/statements/function/dflt-params-trailing-comma.js(default)
-test/language/statements/function/dflt-params-trailing-comma.js(strict mode)
-test/language/statements/function/params-trailing-comma-multiple.js(default)
-test/language/statements/function/params-trailing-comma-multiple.js(strict mode)
-test/language/statements/function/params-trailing-comma-single.js(default)
-test/language/statements/function/params-trailing-comma-single.js(strict mode)
 test/language/statements/generators/dflt-params-ref-later.js(default)
 test/language/statements/generators/dflt-params-ref-later.js(strict mode)
 test/language/statements/generators/dflt-params-ref-self.js(default)
 test/language/statements/generators/dflt-params-ref-self.js(strict mode)
-test/language/statements/generators/dflt-params-trailing-comma.js(default)
-test/language/statements/generators/dflt-params-trailing-comma.js(strict mode)
-test/language/statements/generators/params-trailing-comma-multiple.js(default)
-test/language/statements/generators/params-trailing-comma-multiple.js(strict mode)
-test/language/statements/generators/params-trailing-comma-single.js(default)
-test/language/statements/generators/params-trailing-comma-single.js(strict mode)
 test/language/statements/generators/yield-identifier-non-strict.js(default)
 test/language/statements/generators/yield-identifier-spread-non-strict.js(default)
 test/language/statements/class/accessor-name-inst-computed-yield-expr.js(default)
@@ -7188,42 +7122,18 @@ test/language/statements/class/gen-meth-dflt-params-ref-later.js(default)
 test/language/statements/class/gen-meth-dflt-params-ref-later.js(strict mode)
 test/language/statements/class/gen-meth-dflt-params-ref-self.js(default)
 test/language/statements/class/gen-meth-dflt-params-ref-self.js(strict mode)
-test/language/statements/class/gen-meth-dflt-params-trailing-comma.js(default)
-test/language/statements/class/gen-meth-dflt-params-trailing-comma.js(strict mode)
-test/language/statements/class/gen-meth-params-trailing-comma-multiple.js(default)
-test/language/statements/class/gen-meth-params-trailing-comma-multiple.js(strict mode)
-test/language/statements/class/gen-meth-params-trailing-comma-single.js(default)
-test/language/statements/class/gen-meth-params-trailing-comma-single.js(strict mode)
 test/language/statements/class/gen-meth-static-dflt-params-ref-later.js(default)
 test/language/statements/class/gen-meth-static-dflt-params-ref-later.js(strict mode)
 test/language/statements/class/gen-meth-static-dflt-params-ref-self.js(default)
 test/language/statements/class/gen-meth-static-dflt-params-ref-self.js(strict mode)
-test/language/statements/class/gen-meth-static-dflt-params-trailing-comma.js(default)
-test/language/statements/class/gen-meth-static-dflt-params-trailing-comma.js(strict mode)
-test/language/statements/class/gen-meth-static-params-trailing-comma-multiple.js(default)
-test/language/statements/class/gen-meth-static-params-trailing-comma-multiple.js(strict mode)
-test/language/statements/class/gen-meth-static-params-trailing-comma-single.js(default)
-test/language/statements/class/gen-meth-static-params-trailing-comma-single.js(strict mode)
 test/language/statements/class/meth-dflt-params-ref-later.js(default)
 test/language/statements/class/meth-dflt-params-ref-later.js(strict mode)
 test/language/statements/class/meth-dflt-params-ref-self.js(default)
 test/language/statements/class/meth-dflt-params-ref-self.js(strict mode)
-test/language/statements/class/meth-dflt-params-trailing-comma.js(default)
-test/language/statements/class/meth-dflt-params-trailing-comma.js(strict mode)
-test/language/statements/class/meth-params-trailing-comma-multiple.js(default)
-test/language/statements/class/meth-params-trailing-comma-multiple.js(strict mode)
-test/language/statements/class/meth-params-trailing-comma-single.js(default)
-test/language/statements/class/meth-params-trailing-comma-single.js(strict mode)
 test/language/statements/class/meth-static-dflt-params-ref-later.js(default)
 test/language/statements/class/meth-static-dflt-params-ref-later.js(strict mode)
 test/language/statements/class/meth-static-dflt-params-ref-self.js(default)
 test/language/statements/class/meth-static-dflt-params-ref-self.js(strict mode)
-test/language/statements/class/meth-static-dflt-params-trailing-comma.js(default)
-test/language/statements/class/meth-static-dflt-params-trailing-comma.js(strict mode)
-test/language/statements/class/meth-static-params-trailing-comma-multiple.js(default)
-test/language/statements/class/meth-static-params-trailing-comma-multiple.js(strict mode)
-test/language/statements/class/meth-static-params-trailing-comma-single.js(default)
-test/language/statements/class/meth-static-params-trailing-comma-single.js(strict mode)
 
 # JSHint currently makes no attempt to resolve module references, so it is
 # incapable of detecting early errors across modules.

diff --git a/tests/unit/parser.js b/tests/unit/parser.js
@@ -8908,3 +8908,21 @@ exports.letAsIdentifier = function (test) {
 
   test.done();
 };
+
+exports.trailingParameterComma = function(test) {
+  var code = 'function f(x,) {}';
+
+  TestRun(test, 'declaration in ES5')
+    .addError(1, 13, "'Trailing comma in function parameters' is only available in ES8 (use 'esversion: 8').")
+    .test(code, { esversion: 5 });
+  TestRun(test, 'declaration in ES6')
+    .addError(1, 13, "'Trailing comma in function parameters' is only available in ES8 (use 'esversion: 8').")
+    .test(code, { esversion: 6 });
+  TestRun(test, 'declaration in ES7')
+    .addError(1, 13, "'Trailing comma in function parameters' is only available in ES8 (use 'esversion: 8').")
+    .test(code, { esversion: 7 });
+  TestRun(test, 'declaration in ES8')
+    .test(code, { esversion: 8 });
+
+  test.done();
+};