[[FEAT]] Enable object rest/spread via esversion

The "Object rest/spread properties" feature was standardized in ES2018.
Update enabling mechanism to use a new `esversion` value dedicated to
that edition.

package.json

@@ -34,7 +34,7 @@
     "test-cli": "nodeunit tests/cli.js",
     "test-node": "npm run test-unit && npm run test-cli && npm run test-regression",
     "test-regression": "nodeunit tests/regression",
-    "test-unit": "nodeunit tests/unit tests/unit/unstable",
+    "test-unit": "nodeunit tests/unit",
     "test": "npm run test-node && npm run test-browser"
   },
   "main": "./src/jshint.js",

src/jshint.js

@@ -3877,8 +3877,8 @@ var JSHINT = (function() {
           }
 
         } else if (spreadrest("spread")) {
-          if (!state.option.unstable.objspreadrest) {
-            warning("W144", state.tokens.next, "object spread property", "objspreadrest");
+          if (!state.inES9()) {
+            warning("W119", state.tokens.next, "object spread property", "9");
           }
 
           expression(10, context);
@@ -4024,8 +4024,8 @@ var JSHINT = (function() {
         var isRest = spreadrest("rest");
 
         if (isRest) {
-          if (!state.option.unstable.objspreadrest) {
-            warning("W144", state.tokens.next, "object rest property", "objspreadrest");
+          if (!state.inES9()) {
+            warning("W119", state.tokens.next, "object rest property", "9");
           }
 
           // Due to visual symmetry with the array rest property (and the early

src/options.js

@@ -1027,32 +1027,6 @@ exports.val = {
  * right to remove or modify them between major version releases.
  */
 exports.unstable = {
-  /**
-   * Enable parsing support for rest properties for object destructuring
-   * assignment and spread properties for object literals. From the proposal:
-   *
-   * > Rest Properties
-   * >
-   * > Rest properties collect the remaining own enumerable property keys that
-   * > are not already picked off by the destructuring pattern. Those keys and
-   * > their values are copied onto a new object.
-   * >
-   * >     let { x, y, ...z } = { x: 1, y: 2, a: 3, b: 4 };
-   * >     x; // 1
-   * >     y; // 2
-   * >     z; // { a: 3, b: 4 }
-   * >
-   * > Spread Properties
-   * >
-   * > Spread properties in object initializers copies own enumerable
-   * > properties from a provided object onto the newly created object.
-   * >
-   * >     let n = { x, y, ...z };
-   * >     n; // { x: 1, y: 2, a: 3, b: 4 }
-   *
-   * https://github.com/tc39/proposal-object-rest-spread
-   */
-  objspreadrest: true
 };
 
 // These are JSHint boolean options which are shared with JSLint

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}
+   */
+  inES9: function() {
+    return this.esVersion >= 9;
+  },
+
   /**
    * Determine if constructs introduced in ECMAScript 8 should be accepted.
    *

tests/test262/test.js

@@ -49,7 +49,7 @@ module.exports = function(test) {
   var isModule = !!test.attrs.flags.module;
 
   try {
-    JSHint(test.contents, { esversion: 8, maxerr: Infinity, module: isModule });
+    JSHint(test.contents, { esversion: 9, maxerr: Infinity, module: isModule });
   } catch (e) {
     return false;
   }

tests/unit/unstable/objrestspread.js → tests/unit/objrestspread.js

@@ -1,15 +1,15 @@
 "use strict";
 
-var TestRun = require("../../helpers/testhelper").setup.testRun;
+var TestRun = require("../helpers/testhelper").setup.testRun;
 
 exports.enabling = function (test) {
   TestRun(test, "Not enabled")
-    .addError(1, 11, "'object spread property' is a non-standard language feature. Enable it using the 'objspreadrest' unstable option.")
-    .test("void { ...x };", { esversion: 6 });
+    .addError(1, 11, "'object spread property' is only available in ES9 (use 'esversion: 9').")
+    .test("void { ...x };", { esversion: 8 });
 
   TestRun(test, "Not enabled")
-    .addError(1, 7, "'object rest property' is a non-standard language feature. Enable it using the 'objspreadrest' unstable option.")
-    .test("({ ...x } = {});", { esversion: 6 });
+    .addError(1, 7, "'object rest property' is only available in ES9 (use 'esversion: 9').")
+    .test("({ ...x } = {});", { esversion: 8 });
 
   test.done();
 };
@@ -24,7 +24,7 @@ exports.spread = function (test) {
   ];
 
   TestRun(test, "identifier")
-    .test(code, { esversion: 6, unstable: { objspreadrest: true } });
+    .test(code, { esversion: 9 });
 
   code = [
     "var o;",
@@ -37,7 +37,7 @@ exports.spread = function (test) {
   ];
 
   TestRun(test, "expression")
-    .test(code, { esversion: 6, unstable: { objspreadrest: true } });
+    .test(code, { esversion: 9 });
 
   test.done();
 };
@@ -52,7 +52,7 @@ exports.rest = function (test) {
   ];
 
   TestRun(test, "identifier, final")
-    .test(code, { esversion: 6, unstable: { objspreadrest: true } });
+    .test(code, { esversion: 9 });
 
   code = [
     "({ ...x, } = {});",
@@ -68,7 +68,7 @@ exports.rest = function (test) {
     .addError(3, 15, "Invalid element after rest element.")
     .addError(4, 14, "Invalid element after rest element.")
     .addError(5, 18, "Invalid element after rest element.")
-    .test(code, { esversion: 6, unstable: { objspreadrest: true } });
+    .test(code, { esversion: 9 });
 
   code = [
     "({ ...[a, b, c] } = {});",
@@ -84,7 +84,7 @@ exports.rest = function (test) {
     .addError(3, 14, "Expected an identifier and instead saw '['.")
     .addError(4, 13, "Expected an identifier and instead saw '['.")
     .addError(5, 17, "Expected an identifier and instead saw '['.")
-    .test(code, { esversion: 6, unstable: { objspreadrest: true } });
+    .test(code, { esversion: 9 });
 
   code = [
     "({ ...[a, b, c], } = {});",
@@ -105,15 +105,15 @@ exports.rest = function (test) {
     .addError(4, 22, "Invalid element after rest element.")
     .addError(5, 17, "Expected an identifier and instead saw '['.")
     .addError(5, 26, "Invalid element after rest element.")
-    .test(code, { esversion: 6, unstable: { objspreadrest: true } });
+    .test(code, { esversion: 9 });
 
   TestRun(test, "nested array pattern, empty")
     .addError(1, 7, "Expected an identifier and instead saw '['.")
-    .test("({ ...[] } = {});", { esversion: 6, unstable: { objspreadrest: true } });
+    .test("({ ...[] } = {});", { esversion: 9 });
 
   TestRun(test, "nested object pattern, empty")
     .addError(1, 7, "Expected an identifier and instead saw '{'.")
-    .test("({ ...{} } = {});", { esversion: 6, unstable: { objspreadrest: true } });
+    .test("({ ...{} } = {});", { esversion: 9 });
 
   test.done();
 };