Create @babel/plugin-proposal-dynamic-import (#9552)

* Create @babel/plugin-proposal-dynamic-import

* Use airbnb/babel-plugin-dynamic-import-node

Do not duplicate code, which will unavoidably lead
to bugs being fixed in one plugin and not in the other.

* Update error message

* Add error callback to amd interop

* Update babel-plugin-dynamic-import-node

packages/babel-plugin-transform-modules-systemjs/package.json

@@ -10,7 +10,8 @@
   "main": "lib/index.js",
   "dependencies": {
     "@babel/helper-hoist-variables": "^7.4.4",
-    "@babel/helper-plugin-utils": "^7.0.0"
+    "@babel/helper-plugin-utils": "^7.0.0",
+    "babel-plugin-dynamic-import-node": "^2.3.0"
   },
   "keywords": [
     "babel-plugin"

packages/babel-plugin-transform-modules-systemjs/src/index.js

@@ -1,6 +1,7 @@
 import { declare } from "@babel/helper-plugin-utils";
 import hoistVariables from "@babel/helper-hoist-variables";
 import { template, types as t } from "@babel/core";
+import { getImportSource } from "babel-plugin-dynamic-import-node/utils";
 
 const buildTemplate = template(`
   SYSTEM_REGISTER(MODULE_NAME, SOURCES, function (EXPORT_IDENTIFIER, CONTEXT_IDENTIFIER) {
@@ -21,6 +22,12 @@ const buildExportAll = template(`
   }
 `);
 
+const MISSING_PLUGIN_WARNING = `\
+WARNING: Dynamic import() transformation must be enabled using the
+         @babel/plugin-proposal-dynamic-import plugin. Babel 8 will
+         no longer transform import() without using that plugin.
+`;
+
 function constructExportCall(
   path,
   exportIdent,
@@ -96,8 +103,6 @@ function constructExportCall(
   return statements;
 }
 
-const TYPE_IMPORT = "Import";
-
 export default declare((api, options) => {
   api.assertVersion(7);
 
@@ -168,16 +173,24 @@ export default declare((api, options) => {
   return {
     name: "transform-modules-systemjs",
 
+    pre() {
+      this.file.set("@babel/plugin-transform-modules-*", "systemjs");
+    },
+
     visitor: {
       CallExpression(path, state) {
-        if (path.node.callee.type === TYPE_IMPORT) {
+        if (t.isImport(path.node.callee)) {
+          if (!this.file.has("@babel/plugin-proposal-dynamic-import")) {
+            console.warn(MISSING_PLUGIN_WARNING);
+          }
+
           path.replaceWith(
             t.callExpression(
               t.memberExpression(
                 t.identifier(state.contextIdent),
                 t.identifier("import"),
               ),
-              path.node.arguments,
+              [getImportSource(t, path.node)],
             ),
           );
         }

packages/babel-plugin-transform-modules-systemjs/test/fixtures/dynamic-import/dynamic-import/input.mjs

@@ -1,6 +0,0 @@
-export function lazyLoadOperation () {
-  return import('./x')
-  .then(function (x) {
-    x.y();
-  });
-}

packages/babel-plugin-transform-modules-systemjs/test/fixtures/dynamic-import/dynamic-import/output.mjs

@@ -1,16 +0,0 @@
-System.register([], function (_export, _context) {
-  "use strict";
-
-  function lazyLoadOperation() {
-    return _context.import('./x').then(function (x) {
-      x.y();
-    });
-  }
-
-  _export("lazyLoadOperation", lazyLoadOperation);
-
-  return {
-    setters: [],
-    execute: function () {}
-  };
-});