Add createImportExpressions parser option (#15682)

Co-authored-by: Nicolò Ribaudo <hello@nicr.dev>
Co-authored-by: liuxingbaoyu <30521560+liuxingbaoyu@users.noreply.github.com>

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

@@ -312,3 +312,15 @@ export function ImportNamespaceSpecifier(
   this.space();
   this.print(node.local, node);
 }
+
+export function ImportExpression(this: Printer, node: t.ImportExpression) {
+  this.word("import");
+  this.token("(");
+  this.print(node.source, node);
+  if (node.options != null) {
+    this.token(",");
+    this.space();
+    this.print(node.options, node);
+  }
+  this.token(")");
+}

packages/babel-generator/test/fixtures/comments/dynamic-import/input.js

@@ -0,0 +1 @@
+/*0*/import/*1*/(/*2*/"foo"/*3*/)/*4*/

packages/babel-generator/test/fixtures/comments/dynamic-import/options.json

@@ -0,0 +1,5 @@
+{
+  "parserOpts": {
+    "createImportExpressions": true
+  }
+}

packages/babel-generator/test/fixtures/comments/dynamic-import/output.js

@@ -0,0 +1 @@
+/*0*/import /*1*/( /*2*/"foo" /*3*/); /*4*/

packages/babel-generator/test/fixtures/types/Import-createImportExpression-false/input.js

@@ -0,0 +1 @@
+import("module.js");

packages/babel-generator/test/fixtures/types/Import-createImportExpression-false/options.json

@@ -0,0 +1 @@
+{ "parserOpts": { "createImportExpressions": false } }

packages/babel-generator/test/fixtures/types/Import-createImportExpression-false/output.js

@@ -0,0 +1 @@
+import("module.js");

packages/babel-generator/test/fixtures/types/Import/options.json

@@ -1 +1 @@
-{ "plugins": ["dynamicImport"] }
+{ "parserOpts": { "createImportExpressions": true } }

packages/babel-generator/test/fixtures/types/ImportAttribute-createImportExpression-false/input.js

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

packages/babel-generator/test/fixtures/types/ImportAttribute-createImportExpression-false/options.json

@@ -0,0 +1,5 @@
+{
+  "plugins": [["importAttributes", { "importAttributesKeyword": "with" }]],
+  "sourceType": "module",
+  "parserOpts": { "createImportExpressions": false }
+}

packages/babel-generator/test/fixtures/types/ImportAttribute-createImportExpression-false/output.js

@@ -0,0 +1,5 @@
+import("foo.json", {
+  with: {
+    type: "json"
+  }
+});

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

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

packages/babel-generator/test/fixtures/types/ImportAttribute/options.json

@@ -0,0 +1,5 @@
+{
+  "plugins": [["importAttributes", { "importAttributesKeyword": "with" }]],
+  "sourceType": "module",
+  "parserOpts": { "createImportExpressions": true }
+}

packages/babel-generator/test/fixtures/types/ImportAttribute/output.js

@@ -0,0 +1,5 @@
+import("foo.json", {
+  with: {
+    type: "json"
+  }
+});

packages/babel-helper-module-transforms/src/dynamic-import.ts

@@ -17,12 +17,12 @@ if (!process.env.BABEL_8_BREAKING && !USE_ESM && !IS_STANDALONE) {
 }
 
 export function buildDynamicImport(
-  node: t.CallExpression,
+  node: t.CallExpression | t.ImportExpression,
   deferToThen: boolean,
   wrapWithPromise: boolean,
   builder: (specifier: t.Expression) => t.Expression,
 ): t.Expression {
-  const [specifier] = node.arguments;
+  const specifier = t.isCallExpression(node) ? node.arguments[0] : node.source;
 
   if (
     t.isStringLiteral(specifier) ||

packages/babel-helper-module-transforms/src/index.ts

@@ -165,7 +165,7 @@ export function ensureStatementsHoisted(statements: t.Statement[]) {
  * wrap it in a call to the interop helpers based on the type.
  */
 export function wrapInterop(
-  programPath: NodePath,
+  programPath: NodePath<t.Program>,
   expr: t.Expression,
   type: InteropType,
 ): t.CallExpression {

packages/babel-parser/data/schema.json

@@ -68,6 +68,11 @@
       "description": "By default, exported identifiers must refer to a declared variable.\nSet this to true to allow export statements to reference undeclared variables.",
       "type": "boolean"
     },
+    "createImportExpressions": {
+      "description": "By default, `import(foo)` is parsed as `CallExpression(Import, [Identifier(foo)])`.\nSet this to true to parse it as an `ImportExpression` node.",
+      "type": "boolean",
+      "default": false
+    },
     "createParenthesizedExpressions": {
       "description": "By default, the parser adds information about parentheses by setting\n`extra.parenthesized` to `true` as needed.\nWhen this option is `true` the parser creates `ParenthesizedExpression`\nAST nodes instead of using the `extra` property.",
       "type": "boolean"

packages/babel-parser/src/options.ts

@@ -20,6 +20,7 @@ export type Options = {
   strictMode: boolean | undefined | null;
   ranges: boolean;
   tokens: boolean;
+  createImportExpressions: boolean;
   createParenthesizedExpressions: boolean;
   errorRecovery: boolean;
   attachComment: boolean;
@@ -68,6 +69,9 @@ export const defaultOptions: Options = {
   ranges: false,
   // Adds all parsed tokens to a `tokens` property on the `File` node
   tokens: false,
+  // Whether to create ImportExpression AST nodes (if false
+  // `import(foo)` will be parsed as CallExpression(Import, [Identifier(foo)])
+  createImportExpressions: false,
   // Whether to create ParenthesizedExpression AST nodes (if false
   // the parser sets extra.parenthesized on the expression nodes instead).
   createParenthesizedExpressions: false,

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

@@ -1110,19 +1110,26 @@ export default abstract class ExpressionParser extends LValParser {
         return this.parseSuper();
 
       case tt._import:
-        node = this.startNode<N.MetaProperty | N.Import>();
+        node = this.startNode<N.MetaProperty | N.Import | N.ImportExpression>();
         this.next();
 
         if (this.match(tt.dot)) {
           return this.parseImportMetaProperty(node as Undone<N.MetaProperty>);
         }
 
-        if (!this.match(tt.parenL)) {
+        if (this.match(tt.parenL)) {
+          if (this.options.createImportExpressions) {
+            return this.parseImportCall(node as Undone<N.ImportExpression>);
+          } else {
+            return this.finishNode(node, "Import");
+          }
+        } else {
           this.raise(Errors.UnsupportedImport, {
             at: this.state.lastTokStartLoc,
           });
+          return this.finishNode(node, "Import");
         }
-        return this.finishNode(node, "Import");
+
       case tt._this:
         node = this.startNode();
         this.next();
@@ -1920,9 +1927,14 @@ export default abstract class ExpressionParser extends LValParser {
   }
 
   parseNewCallee(this: Parser, node: Undone<N.NewExpression>): void {
-    node.callee = this.parseNoCallExpr();
-    if (node.callee.type === "Import") {
-      this.raise(Errors.ImportCallNotNewExpression, { at: node.callee });
+    const isImport = this.match(tt._import);
+    const callee = this.parseNoCallExpr();
+    node.callee = callee;
+    if (
+      isImport &&
+      (callee.type === "Import" || callee.type === "ImportExpression")
+    ) {
+      this.raise(Errors.ImportCallNotNewExpression, { at: callee });
     }
   }
 
@@ -2939,6 +2951,30 @@ export default abstract class ExpressionParser extends LValParser {
     return this.finishNode(node, "YieldExpression");
   }
 
+  // https://tc39.es/ecma262/#prod-ImportCall
+  parseImportCall(
+    this: Parser,
+    node: Undone<N.ImportExpression>,
+  ): N.ImportExpression {
+    this.next(); // eat tt.parenL
+    node.source = this.parseMaybeAssignAllowIn();
+    if (
+      this.hasPlugin("importAttributes") ||
+      this.hasPlugin("importAssertions")
+    ) {
+      node.options = null;
+    }
+    if (this.eat(tt.comma)) {
+      this.expectImportAttributesPlugin();
+      if (!this.match(tt.parenR)) {
+        node.options = this.parseMaybeAssignAllowIn();
+        this.eat(tt.comma);
+      }
+    }
+    this.expect(tt.parenR);
+    return this.finishNode(node, "ImportExpression");
+  }
+
   // Validates a pipeline (for any of the pipeline Babylon plugins) at the point
   // of the infix operator `|>`.
 

packages/babel-parser/src/plugins/estree.ts

@@ -424,6 +424,9 @@ export default (superClass: typeof Parser) =>
           this.hasPlugin("importAttributes") ||
           this.hasPlugin("importAssertions")
         ) {
+          (node as N.Node as N.EstreeImportExpression).options =
+            node.arguments[1] ?? null;
+          // compatibility with previous ESTree AST
           (node as N.Node as N.EstreeImportExpression).attributes =
             node.arguments[1] ?? null;
         }

packages/babel-parser/src/types.d.ts

@@ -624,6 +624,12 @@ export interface NewExpression extends CallOrNewBase {
   optional?: boolean; // TODO: Not in spec
 }
 
+export interface ImportExpression extends NodeBase {
+  type: "ImportExpression";
+  source: Expression;
+  options: Expression | null;
+}
+
 export interface SequenceExpression extends NodeBase {
   type: "SequenceExpression";
   expressions: Expression[];
@@ -1213,6 +1219,10 @@ export interface EstreeMethodDefinition extends NodeBase {
 export interface EstreeImportExpression extends NodeBase {
   type: "ImportExpression";
   source: Expression;
+  options?: Expression | null;
+  /**
+   * @deprecated Use options instead
+   */
   attributes?: Expression | null;
 }
 

packages/babel-parser/test/fixtures/es2020/dynamic-import-createImportExpression-false/direct-calls-only/input.js

@@ -0,0 +1,3 @@
+function failsParse() {
+  return import.then();
+}

packages/babel-parser/test/fixtures/es2020/dynamic-import-createImportExpression-false/direct-calls-only/output.json

@@ -0,0 +1,58 @@
+{
+  "type": "File",
+  "start":0,"end":49,"loc":{"start":{"line":1,"column":0,"index":0},"end":{"line":3,"column":1,"index":49}},
+  "errors": [
+    "SyntaxError: The only valid meta property for import is import.meta. (2:16)"
+  ],
+  "program": {
+    "type": "Program",
+    "start":0,"end":49,"loc":{"start":{"line":1,"column":0,"index":0},"end":{"line":3,"column":1,"index":49}},
+    "sourceType": "script",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "FunctionDeclaration",
+        "start":0,"end":49,"loc":{"start":{"line":1,"column":0,"index":0},"end":{"line":3,"column":1,"index":49}},
+        "id": {
+          "type": "Identifier",
+          "start":9,"end":19,"loc":{"start":{"line":1,"column":9,"index":9},"end":{"line":1,"column":19,"index":19},"identifierName":"failsParse"},
+          "name": "failsParse"
+        },
+        "generator": false,
+        "async": false,
+        "params": [],
+        "body": {
+          "type": "BlockStatement",
+          "start":22,"end":49,"loc":{"start":{"line":1,"column":22,"index":22},"end":{"line":3,"column":1,"index":49}},
+          "body": [
+            {
+              "type": "ReturnStatement",
+              "start":26,"end":47,"loc":{"start":{"line":2,"column":2,"index":26},"end":{"line":2,"column":23,"index":47}},
+              "argument": {
+                "type": "CallExpression",
+                "start":33,"end":46,"loc":{"start":{"line":2,"column":9,"index":33},"end":{"line":2,"column":22,"index":46}},
+                "callee": {
+                  "type": "MetaProperty",
+                  "start":33,"end":44,"loc":{"start":{"line":2,"column":9,"index":33},"end":{"line":2,"column":20,"index":44}},
+                  "meta": {
+                    "type": "Identifier",
+                    "start":33,"end":39,"loc":{"start":{"line":2,"column":9,"index":33},"end":{"line":2,"column":15,"index":39},"identifierName":"import"},
+                    "name": "import"
+                  },
+                  "property": {
+                    "type": "Identifier",
+                    "start":40,"end":44,"loc":{"start":{"line":2,"column":16,"index":40},"end":{"line":2,"column":20,"index":44},"identifierName":"then"},
+                    "name": "then"
+                  }
+                },
+                "arguments": []
+              }
+            }
+          ],
+          "directives": []
+        }
+      }
+    ],
+    "directives": []
+  }
+}

packages/babel-parser/test/fixtures/es2020/dynamic-import-createImportExpression-false/generator/input.js

@@ -0,0 +1,3 @@
+function* a() {
+  yield import('http');
+}

packages/babel-parser/test/fixtures/es2020/dynamic-import-createImportExpression-false/generator/output.json

@@ -0,0 +1,60 @@
+{
+  "type": "File",
+  "start":0,"end":41,"loc":{"start":{"line":1,"column":0,"index":0},"end":{"line":3,"column":1,"index":41}},
+  "program": {
+    "type": "Program",
+    "start":0,"end":41,"loc":{"start":{"line":1,"column":0,"index":0},"end":{"line":3,"column":1,"index":41}},
+    "sourceType": "script",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "FunctionDeclaration",
+        "start":0,"end":41,"loc":{"start":{"line":1,"column":0,"index":0},"end":{"line":3,"column":1,"index":41}},
+        "id": {
+          "type": "Identifier",
+          "start":10,"end":11,"loc":{"start":{"line":1,"column":10,"index":10},"end":{"line":1,"column":11,"index":11},"identifierName":"a"},
+          "name": "a"
+        },
+        "generator": true,
+        "async": false,
+        "params": [],
+        "body": {
+          "type": "BlockStatement",
+          "start":14,"end":41,"loc":{"start":{"line":1,"column":14,"index":14},"end":{"line":3,"column":1,"index":41}},
+          "body": [
+            {
+              "type": "ExpressionStatement",
+              "start":18,"end":39,"loc":{"start":{"line":2,"column":2,"index":18},"end":{"line":2,"column":23,"index":39}},
+              "expression": {
+                "type": "YieldExpression",
+                "start":18,"end":38,"loc":{"start":{"line":2,"column":2,"index":18},"end":{"line":2,"column":22,"index":38}},
+                "delegate": false,
+                "argument": {
+                  "type": "CallExpression",
+                  "start":24,"end":38,"loc":{"start":{"line":2,"column":8,"index":24},"end":{"line":2,"column":22,"index":38}},
+                  "callee": {
+                    "type": "Import",
+                    "start":24,"end":30,"loc":{"start":{"line":2,"column":8,"index":24},"end":{"line":2,"column":14,"index":30}}
+                  },
+                  "arguments": [
+                    {
+                      "type": "StringLiteral",
+                      "start":31,"end":37,"loc":{"start":{"line":2,"column":15,"index":31},"end":{"line":2,"column":21,"index":37}},
+                      "extra": {
+                        "rawValue": "http",
+                        "raw": "'http'"
+                      },
+                      "value": "http"
+                    }
+                  ]
+                }
+              }
+            }
+          ],
+          "directives": []
+        }
+      }
+    ],
+    "directives": []
+  }
+}

packages/babel-parser/test/fixtures/es2020/dynamic-import-createImportExpression-false/inside-function/input.js

@@ -0,0 +1,3 @@
+function loadImport(file) {
+  return import(`test/${file}.js`);
+}