fix: restore moduleAttributes support

packages/babel-generator/src/generators/modules.js

@@ -190,6 +190,15 @@ export function ImportDeclaration(node: Object) {
     this.space();
     this.token("}");
   }
+  // todo(Babel 8): remove this if branch
+  // `module-attributes` support is discontinued, use `import-assertions` instead.
+  else if (node.attributes?.length) {
+    this.space();
+    this.word("with");
+    this.space();
+    this.space();
+    this.printList(node.attributes, node);
+  }
 
   this.semicolon();
 }

packages/babel-generator/test/fixtures/types/ModuleAttributes/input.js

@@ -0,0 +1,3 @@
+import "foo.json" with type: "json";
+import("foo.json", { with: { type: "json" } },);
+

packages/babel-generator/test/fixtures/types/Import2/options.json → packages/babel-generator/test/fixtures/types/ModuleAttributes/options.json

@@ -1,9 +1,9 @@
 {
   "plugins": [
     [
-      "importAssertions",
+      "moduleAttributes",
       {
-        "version": "september-2020"
+        "version": "may-2020"
       }
     ]
   ],

packages/babel-generator/test/fixtures/types/Import2/output.js → packages/babel-generator/test/fixtures/types/ModuleAttributes/output.js

@@ -1,3 +1,4 @@
+import "foo.json" with type: "json";
 import("foo.json", {
   with: {
     type: "json"

packages/babel-parser/src/parser/expression.js

@@ -829,13 +829,18 @@ export default class ExpressionParser extends LValParser {
   ): N.Expression {
     if (node.callee.type === "Import") {
       if (node.arguments.length === 2) {
-        this.expectPlugin("importAssertions");
+        // todo(Babel 8): remove the if condition,
+        // moduleAttributes is renamed to importAssertions
+        if (!this.hasPlugin("moduleAttributes")) {
+          this.expectPlugin("importAssertions");
+        }
       }
       if (node.arguments.length === 0 || node.arguments.length > 2) {
         this.raise(
           node.start,
           Errors.ImportCallArity,
-          this.hasPlugin("importAssertions")
+          this.hasPlugin("importAssertions") ||
+            this.hasPlugin("moduleAttributes")
             ? "one or two arguments"
             : "one argument",
         );
@@ -872,7 +877,11 @@ export default class ExpressionParser extends LValParser {
       } else {
         this.expect(tt.comma);
         if (this.match(close)) {
-          if (dynamicImport && !this.hasPlugin("importAssertions")) {
+          if (
+            dynamicImport &&
+            !this.hasPlugin("importAssertions") &&
+            !this.hasPlugin("moduleAttributes")
+          ) {
             this.raise(
               this.state.lastTokStart,
               Errors.ImportCallArgumentTrailingComma,

packages/babel-parser/src/parser/statement.js

@@ -2084,6 +2084,14 @@ export default class StatementParser extends ExpressionParser {
     if (assertions) {
       node.assertions = assertions;
     }
+    // todo(Babel 8): remove module attributes support
+    else {
+      const attributes = this.maybeParseModuleAttributes();
+      if (attributes) {
+        node.attributes = attributes;
+      }
+    }
+
     this.semicolon();
     return this.finishNode(node, "ImportDeclaration");
   }
@@ -2171,6 +2179,57 @@ export default class StatementParser extends ExpressionParser {
     return attrs;
   }
 
+  /**
+   * parse module attributes
+   * @deprecated It will be removed in Babel 8
+   * @returns
+   * @memberof StatementParser
+   */
+  maybeParseModuleAttributes() {
+    if (this.match(tt._with) && !this.hasPrecedingLineBreak()) {
+      this.expectPlugin("moduleAttributes");
+      this.next();
+    } else {
+      if (this.hasPlugin("moduleAttributes")) return [];
+      return null;
+    }
+    const attrs = [];
+    const attributes = new Set();
+    do {
+      const node = this.startNode();
+      node.key = this.parseIdentifier(true);
+
+      if (node.key.name !== "type") {
+        this.raise(
+          node.key.start,
+          Errors.ModuleAttributeDifferentFromType,
+          node.key.name,
+        );
+      }
+
+      if (attributes.has(node.key.name)) {
+        this.raise(
+          node.key.start,
+          Errors.ModuleAttributesWithDuplicateKeys,
+          node.key.name,
+        );
+      }
+      attributes.add(node.key.name);
+      this.expect(tt.colon);
+      if (!this.match(tt.string)) {
+        throw this.unexpected(
+          this.state.start,
+          Errors.ModuleAttributeInvalidValue,
+        );
+      }
+      node.value = this.parseLiteral(this.state.value, "StringLiteral");
+      this.finishNode(node, "ImportAttribute");
+      attrs.push(node);
+    } while (this.eat(tt.comma));
+
+    return attrs;
+  }
+
   maybeParseImportAssertions() {
     if (
       this.match(tt.name) &&

packages/babel-parser/src/plugin-utils.js

@@ -86,6 +86,21 @@ export function validatePlugins(plugins: PluginList) {
     );
   }
 
+  if (hasPlugin(plugins, "moduleAttributes")) {
+    const moduleAttributesVerionPluginOption = getPluginOption(
+      plugins,
+      "moduleAttributes",
+      "version",
+    );
+    if (moduleAttributesVerionPluginOption !== "may-2020") {
+      throw new Error(
+        "The 'moduleAttributes' plugin requires a 'version' option," +
+          " representing the last proposal update. Currently, the" +
+          " only supported value is 'may-2020'.",
+      );
+    }
+  }
+
   if (hasPlugin(plugins, "importAssertions")) {
     const importAssertionsVerionPluginOption = getPluginOption(
       plugins,
@@ -99,6 +114,11 @@ export function validatePlugins(plugins: PluginList) {
           " only supported value is 'september-2020'.",
       );
     }
+    if (hasPlugin(plugins, "moduleAttributes")) {
+      throw new Error(
+        "Cannot combine importAssertions and moduleAttributes plugins.",
+      );
+    }
   }
   if (
     hasPlugin(plugins, "recordAndTuple") &&

packages/babel-parser/test/fixtures/experimental/_no-plugin/module-attributes/input.js

@@ -1 +1 @@
-import foo from "foo.json" assert { type: "json" };
+import foo from "foo.json" with type: "json";

packages/babel-parser/test/fixtures/experimental/_no-plugin/module-attributes/options.json

@@ -0,0 +1,3 @@
+{
+  "throws": "This experimental syntax requires enabling the parser plugin: 'moduleAttributes' (1:27)"
+}

packages/babel-parser/test/fixtures/experimental/module-attributes/dynamic-import-with-valid-syntax/input.js

@@ -0,0 +1 @@
+import("foo.json", { with: { type: "json" } })

packages/babel-parser/test/fixtures/experimental/module-attributes/dynamic-import-with-valid-syntax/options.json

@@ -0,0 +1,11 @@
+{
+  "plugins": [
+    [
+      "moduleAttributes",
+      {
+        "version": "may-2020"
+      }
+    ]
+  ],
+  "sourceType": "module"
+}

packages/babel-parser/test/fixtures/experimental/module-attributes/dynamic-import-with-valid-syntax/output.json

@@ -0,0 +1,81 @@
+{
+  "type": "File",
+  "start":0,"end":46,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":46}},
+  "program": {
+    "type": "Program",
+    "start":0,"end":46,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":46}},
+    "sourceType": "module",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "ExpressionStatement",
+        "start":0,"end":46,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":46}},
+        "expression": {
+          "type": "CallExpression",
+          "start":0,"end":46,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":46}},
+          "callee": {
+            "type": "Import",
+            "start":0,"end":6,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":6}}
+          },
+          "arguments": [
+            {
+              "type": "StringLiteral",
+              "start":7,"end":17,"loc":{"start":{"line":1,"column":7},"end":{"line":1,"column":17}},
+              "extra": {
+                "rawValue": "foo.json",
+                "raw": "\"foo.json\""
+              },
+              "value": "foo.json"
+            },
+            {
+              "type": "ObjectExpression",
+              "start":19,"end":45,"loc":{"start":{"line":1,"column":19},"end":{"line":1,"column":45}},
+              "properties": [
+                {
+                  "type": "ObjectProperty",
+                  "start":21,"end":43,"loc":{"start":{"line":1,"column":21},"end":{"line":1,"column":43}},
+                  "method": false,
+                  "key": {
+                    "type": "Identifier",
+                    "start":21,"end":25,"loc":{"start":{"line":1,"column":21},"end":{"line":1,"column":25},"identifierName":"with"},
+                    "name": "with"
+                  },
+                  "computed": false,
+                  "shorthand": false,
+                  "value": {
+                    "type": "ObjectExpression",
+                    "start":27,"end":43,"loc":{"start":{"line":1,"column":27},"end":{"line":1,"column":43}},
+                    "properties": [
+                      {
+                        "type": "ObjectProperty",
+                        "start":29,"end":41,"loc":{"start":{"line":1,"column":29},"end":{"line":1,"column":41}},
+                        "method": false,
+                        "key": {
+                          "type": "Identifier",
+                          "start":29,"end":33,"loc":{"start":{"line":1,"column":29},"end":{"line":1,"column":33},"identifierName":"type"},
+                          "name": "type"
+                        },
+                        "computed": false,
+                        "shorthand": false,
+                        "value": {
+                          "type": "StringLiteral",
+                          "start":35,"end":41,"loc":{"start":{"line":1,"column":35},"end":{"line":1,"column":41}},
+                          "extra": {
+                            "rawValue": "json",
+                            "raw": "\"json\""
+                          },
+                          "value": "json"
+                        }
+                      }
+                    ]
+                  }
+                }
+              ]
+            }
+          ]
+        }
+      }
+    ],
+    "directives": []
+  }
+}

packages/babel-parser/test/fixtures/experimental/module-attributes/import-with-statement/input.js

@@ -0,0 +1,2 @@
+import "x"
+with ({});

packages/babel-parser/test/fixtures/experimental/module-attributes/import-with-statement/options.json

@@ -0,0 +1,12 @@
+{
+  "plugins": [
+    [
+      "moduleAttributes",
+      {
+        "version": "may-2020"
+      }
+    ],
+    "estree"
+  ],
+  "sourceType": "module"
+}

packages/babel-parser/test/fixtures/experimental/module-attributes/import-with-statement/output.json

@@ -0,0 +1,40 @@
+{
+  "type": "File",
+  "start":0,"end":21,"loc":{"start":{"line":1,"column":0},"end":{"line":2,"column":10}},
+  "errors": [
+    "SyntaxError: 'with' in strict mode (2:0)"
+  ],
+  "program": {
+    "type": "Program",
+    "start":0,"end":21,"loc":{"start":{"line":1,"column":0},"end":{"line":2,"column":10}},
+    "sourceType": "module",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "ImportDeclaration",
+        "start":0,"end":10,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":10}},
+        "specifiers": [],
+        "source": {
+          "type": "Literal",
+          "start":7,"end":10,"loc":{"start":{"line":1,"column":7},"end":{"line":1,"column":10}},
+          "value": "x",
+          "raw": "\"x\""
+        },
+        "attributes": []
+      },
+      {
+        "type": "WithStatement",
+        "start":11,"end":21,"loc":{"start":{"line":2,"column":0},"end":{"line":2,"column":10}},
+        "object": {
+          "type": "ObjectExpression",
+          "start":17,"end":19,"loc":{"start":{"line":2,"column":6},"end":{"line":2,"column":8}},
+          "properties": []
+        },
+        "body": {
+          "type": "EmptyStatement",
+          "start":20,"end":21,"loc":{"start":{"line":2,"column":9},"end":{"line":2,"column":10}}
+        }
+      }
+    ]
+  }
+}

packages/babel-parser/test/fixtures/experimental/module-attributes/incorrect-arity/input.js

@@ -0,0 +1,2 @@
+import();
+import("./foo.json", { with: { type: "json"} }, "unsupported");

packages/babel-parser/test/fixtures/experimental/module-attributes/incorrect-arity/options.json

@@ -0,0 +1,11 @@
+{
+  "plugins": [
+    [
+      "moduleAttributes",
+      {
+        "version": "may-2020"
+      }
+    ]
+  ],
+  "sourceType": "module"
+}