[[FEAT]] Add support for dynamic import

Author: jugglinmike

src/jshint.js

@@ -5576,10 +5576,22 @@ var JSHINT = (function() {
       }
     });
 
-    if (!mp) {
+    if (mp) {
+      return mp;
+    }
+
+    if (!checkPunctuator(state.tokens.next, "(")) {
       return state.syntax["(identifier)"].nud.call(this, context);
     }
-    return mp;
+
+    if (!state.inES11()) {
+      warning("W119", state.tokens.curr, "dynamic import", "11");
+    }
+
+    advance("(");
+    expression(context, 10);
+    advance(")");
+    return this;
   });
 
   var importSymbol = stmt("import", function(context) {
@@ -5686,8 +5698,9 @@ var JSHINT = (function() {
   importSymbol.reserved = true;
   importSymbol.meta = { isFutureReservedWord: true, es5: true };
   importSymbol.useFud = function() {
-    return !(checkPunctuator(state.tokens.next, ".") && peek().identifier);
+    return !(checkPunctuators(state.tokens.next, [".", "("]));
   };
+  importSymbol.rbp = 161;
 
   stmt("export", function(context) {
     var ok = true;

src/options.js

@@ -1053,7 +1053,7 @@ exports.val = {
    *    Notable additions: optional catch bindings.
    *  - `11` - To enable language features introduced by ECMAScript 11. Notable
    *    additions: "export * as ns from 'module'", `import.meta`, the nullish
-   *    coalescing operator, and optional chaining.
+   *    coalescing operator, and optional chaining, and dynamic import.
    */
   esversion: 5
 };

tests/test262/expectations.txt

@@ -0,0 +1,62 @@
+/**
+ * Tests for the parser/tokenizer
+ */
+
+"use strict";
+
+var JSHINT  = require("../..").JSHINT;
+var fs    = require('fs');
+var TestRun = require("../helpers/testhelper").setup.testRun;
+var path    = require("path");
+
+exports.dynamicImport = {};
+
+exports.dynamicImport.valid = function (test) {
+  TestRun(test)
+    .test([
+        "import(0);",
+        "import(0 ? 0 : 0);",
+        "(function * () { ",
+        "  import(yield);",
+        "})();",
+        "import(() => {});",
+        "import(async () => {});",
+        "import(x = 0);",
+        "new (import(0))();",
+        "import(import(0));",
+      ], {esversion: 11});
+
+  test.done();
+};
+
+exports.dynamicImport.invalidvalid = function (test) {
+  TestRun(test, "empty")
+    .addError(1, 8, "Expected an identifier and instead saw ')'.")
+    .addError(1, 9, "Expected ')' and instead saw ';'.")
+    .addError(1, 10, "Missing semicolon.")
+    .test("import();", {esversion: 11});
+
+  TestRun(test, "expression")
+    .addError(1, 11, "Expected ')' and instead saw ','.")
+    .addError(1, 12, "Missing semicolon.")
+    .addError(1, 13, "Expected an assignment or function call and instead saw an expression.")
+    .addError(1, 16, "Missing semicolon.")
+    .addError(1, 16, "Expected an identifier and instead saw ')'.")
+    .addError(1, 16, "Expected an assignment or function call and instead saw an expression.")
+    .test("import('a', 'b');", {esversion: 11});
+
+  TestRun(test, "NewExpression")
+    .addError(1, 5, "Unexpected 'import'.")
+    .addError(1, 13, "Missing '()' invoking a constructor.")
+    .test("new import(0);", {esversion: 11});
+
+  test.done();
+};
+
+exports.dynamicImport.esversion = function (test) {
+  TestRun(test)
+    .addError(1, 1, "'dynamic import' is only available in ES11 (use 'esversion: 11').")
+    .test("import(0);", {esversion: 10});
+
+  test.done();
+};