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Add hasDefaultExport to ModuleInfo (#4356)
* Add hasDefaultExport to ModuleInfo * Improve example * Make export information available after loading, detect reexports * Manually fix vulnerability
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Lines changed: 158 additions & 39 deletions

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‎docs/05-plugin-development.md‎

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@@ -164,27 +164,42 @@ The `importer` is the fully resolved id of the importing module. When resolving
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For those cases, the `isEntry` option will tell you if we are resolving a user defined entry point, an emitted chunk, or if the `isEntry` parameter was provided for the [`this.resolve`](guide/en/#thisresolve) context function.
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You can use this for instance as a mechanism to define custom proxy modules for entry points. The following plugin will only expose the default export from entry points while still keeping named exports available for internal usage:
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You can use this for instance as a mechanism to define custom proxy modules for entry points. The following plugin will proxy all entry points to inject a polyfill import.
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```js
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function onlyDefaultForEntriesPlugin() {
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function injectPolyfillPlugin() {
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return {
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name: 'only-default-for-entries',
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name: 'inject-polyfill',
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async resolveId(source, importer, options) {
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if (options.isEntry) {
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// We need to skip this plugin to avoid an infinite loop
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const resolution = await this.resolve(source, importer, { skipSelf: true, ...options });
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// If it cannot be resolved, return `null` so that Rollup displays an error
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if (!resolution) return null;
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// If it cannot be resolved or is external, just return it so that
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// Rollup can display an error
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if (!resolution || resolution.external) return resolution;
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// In the load hook of the proxy, we want to use this.load to find out
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// if the entry has a default export. In the load hook, however, we no
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// longer have the full "resolution" object that may contain meta-data
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// from other plugins that is only added on first load. Therefore we
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// trigger loading here without waiting for it.
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this.load(resolution);
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return `${resolution.id}?entry-proxy`;
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}
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return null;
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},
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load(id) {
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async load(id) {
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if (id.endsWith('?entry-proxy')) {
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const importee = id.slice(0, -'?entry-proxy'.length);
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// Note that this will throw if there is no default export
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return `export {default} from '${importee}';`;
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const entryId = id.slice(0, -'?entry-proxy'.length);
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// We need to load and parse the original entry first because we need
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// to know if it has a default export
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const { hasDefaultExport } = await this.load({ id: entryId });
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let code = `import 'polyfill';export * from ${JSON.stringify(entryId)};`;
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// Namespace reexports do not reexport default, so we need special
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// handling here
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if (hasDefaultExport) {
200+
code += `export { default } from ${JSON.stringify(entryId)};`;
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}
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return code;
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}
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return null;
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}
@@ -673,6 +688,7 @@ type ModuleInfo = {
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id: string; // the id of the module, for convenience
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code: string | null; // the source code of the module, `null` if external or not yet available
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ast: ESTree.Program; // the parsed abstract syntax tree if available
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hasDefaultExport: boolean | null; // is there a default export, `null` if external or not yet available
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isEntry: boolean; // is this a user- or plugin-defined entry point
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isExternal: boolean; // for external modules that are referenced but not included in the graph
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isIncluded: boolean | null; // is the module included after tree-shaking, `null` if external or not yet available
@@ -718,7 +734,7 @@ This allows you to inspect the final content of modules before deciding how to r
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The returned promise will resolve once the module has been fully transformed and parsed but before any imports have been resolved. That means that the resulting `ModuleInfo` will have empty `importedIds`, `dynamicallyImportedIds`, `importedIdResolutions` and `dynamicallyImportedIdResolutions`. This helps to avoid deadlock situations when awaiting `this.load` in a `resolveId` hook. If you are interested in `importedIds` and `dynamicallyImportedIds`, you should implement a `moduleParsed` hook.
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Note that with regard to the `moduleSideEffects`, `syntheticNamedExports` and `meta` options, the same restrictions apply as for the `resolveId` hook: Their values only have an effect if the module has not been loaded yet. Thus, it is very important to use `this.resolve` first to find out if any plugins want to set special values for these options in their `resolveId` hook, and pass these options on to `this.load` if appropriate. The example below showcases how this can be handled to add a proxy module for modules containing a special code comment:
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Note that with regard to the `moduleSideEffects`, `syntheticNamedExports` and `meta` options, the same restrictions apply as for the `resolveId` hook: Their values only have an effect if the module has not been loaded yet. Thus, it is very important to use `this.resolve` first to find out if any plugins want to set special values for these options in their `resolveId` hook, and pass these options on to `this.load` if appropriate. The example below showcases how this can be handled to add a proxy module for modules containing a special code comment. Note the special handling for re-exporting the default export:
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```js
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export default function addProxyPlugin() {
@@ -744,7 +760,16 @@ export default function addProxyPlugin() {
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load(id) {
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if (id.endsWith('?proxy')) {
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const importee = id.slice(0, -'?proxy'.length);
747-
return `console.log('proxy for ${importee}'); export * from ${JSON.stringify(importee)};`;
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// Note that namespace reexports do not reexport default exports
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let code = `console.log('proxy for ${importee}'); export * from ${JSON.stringify(
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importee
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)};`;
767+
// We know that while resolving the proxy, importee was already fully
768+
// loaded and parsed, so we can rely on hasDefaultExport
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if (this.getModuleInfo(importee).hasDefaultExport) {
770+
code += `export { default } from ${JSON.stringify(importee)};`;
771+
}
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return code;
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}
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return null;
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}
@@ -1142,7 +1167,7 @@ function parentPlugin() {
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}
11431168
}
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// ...plugin hooks
1145-
}
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};
11461171
}
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function dependentPlugin() {
@@ -1151,20 +1176,19 @@ function dependentPlugin() {
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name: 'dependent',
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buildStart({ plugins }) {
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const parentName = 'parent';
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const parentPlugin = options.plugins
1155-
.find(plugin => plugin.name === parentName);
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const parentPlugin = options.plugins.find(plugin => plugin.name === parentName);
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if (!parentPlugin) {
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// or handle this silently if it is optional
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throw new Error(`This plugin depends on the "${parentName}" plugin.`);
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}
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// now you can access the API methods in subsequent hooks
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parentApi = parentPlugin.api;
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}
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},
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transform(code, id) {
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if (thereIsAReasonToDoSomething(id)) {
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parentApi.doSomething(id);
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}
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}
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}
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};
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}
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```

‎package-lock.json‎

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‎package.json‎

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@@ -64,7 +64,7 @@
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"@rollup/plugin-json": "^4.1.0",
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"@rollup/plugin-node-resolve": "^13.1.3",
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"@rollup/plugin-replace": "^3.0.1",
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"@rollup/plugin-typescript": "^8.2.5",
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"@rollup/plugin-typescript": "^8.3.0",
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"@rollup/pluginutils": "^4.1.2",
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"@types/node": "^10.17.60",
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"@types/signal-exit": "^3.0.1",
@@ -100,7 +100,7 @@
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"pretty-bytes": "^5.6.0",
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"pretty-ms": "^7.0.1",
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"requirejs": "^2.3.6",
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"rollup": "^2.64.0",
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"rollup": "^2.65.0",
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"rollup-plugin-license": "^2.6.1",
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"rollup-plugin-string": "^3.0.0",
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"rollup-plugin-terser": "^7.0.2",
@@ -111,7 +111,7 @@
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"source-map": "^0.7.3",
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"source-map-support": "^0.5.21",
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"sourcemap-codec": "^1.4.8",
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"systemjs": "^6.11.0",
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"systemjs": "^6.12.1",
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"terser": "^5.10.0",
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"tslib": "^2.3.1",
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"typescript": "^4.5.5",

‎src/ExternalModule.ts‎

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@@ -46,6 +46,7 @@ export default class ExternalModule {
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get dynamicImporters() {
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return dynamicImporters.sort();
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},
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hasDefaultExport: null,
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hasModuleSideEffects,
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id,
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implicitlyLoadedAfterOneOf: EMPTY_ARRAY,

‎src/Module.ts‎

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@@ -277,6 +277,13 @@ export default class Module {
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get dynamicImporters() {
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return module.dynamicImporters.sort();
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},
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get hasDefaultExport() {
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// This information is only valid after parsing
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if (!module.ast) {
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return null;
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}
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return 'default' in module.exports || 'default' in module.reexportDescriptions;
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},
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hasModuleSideEffects,
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id,
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get implicitlyLoadedAfterOneOf() {

‎src/rollup/types.d.ts‎

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@@ -162,6 +162,7 @@ interface ModuleInfo {
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dynamicImporters: readonly string[];
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dynamicallyImportedIdResolutions: readonly ResolvedId[];
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dynamicallyImportedIds: readonly string[];
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hasDefaultExport: boolean | null;
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hasModuleSideEffects: boolean | 'no-treeshake';
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id: string;
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implicitlyLoadedAfterOneOf: readonly string[];

‎test/chunking-form/samples/implicit-dependencies/implicitly-dependent-emitted-entry/_config.js‎

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@@ -73,6 +73,7 @@ module.exports = {
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dynamicallyImportedIdResolutions: [],
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dynamicallyImportedIds: [],
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dynamicImporters: [],
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hasDefaultExport: false,
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hasModuleSideEffects: true,
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id: ID_MAIN,
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implicitlyLoadedAfterOneOf: [],
@@ -143,6 +144,7 @@ module.exports = {
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dynamicallyImportedIdResolutions: [],
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dynamicallyImportedIds: [],
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dynamicImporters: [],
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hasDefaultExport: false,
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hasModuleSideEffects: true,
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id: ID_DEP,
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implicitlyLoadedAfterOneOf: [],

‎test/chunking-form/samples/implicit-dependencies/implicitly-dependent-entry/_config.js‎

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@@ -69,6 +69,7 @@ module.exports = {
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dynamicallyImportedIdResolutions: [],
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dynamicallyImportedIds: [],
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dynamicImporters: [],
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hasDefaultExport: false,
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hasModuleSideEffects: true,
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id: ID_MAIN,
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implicitlyLoadedAfterOneOf: [],
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dynamicallyImportedIdResolutions: [],
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dynamicallyImportedIds: [],
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dynamicImporters: [],
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hasDefaultExport: false,
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hasModuleSideEffects: true,
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id: ID_DEP,
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implicitlyLoadedAfterOneOf: [],

‎test/chunking-form/samples/implicit-dependencies/multiple-dependencies/_config.js‎

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@@ -117,6 +117,7 @@ module.exports = {
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dynamicallyImportedIdResolutions: [],
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dynamicallyImportedIds: [],
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dynamicImporters: [],
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hasDefaultExport: false,
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hasModuleSideEffects: true,
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id: ID_MAIN1,
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implicitlyLoadedAfterOneOf: [],
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dynamicallyImportedIdResolutions: [],
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dynamicallyImportedIds: [],
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dynamicImporters: [],
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hasDefaultExport: false,
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hasModuleSideEffects: true,
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id: ID_MAIN2,
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implicitlyLoadedAfterOneOf: [],
@@ -354,6 +356,7 @@ module.exports = {
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dynamicallyImportedIdResolutions: [],
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dynamicallyImportedIds: [],
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dynamicImporters: [],
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hasDefaultExport: false,
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hasModuleSideEffects: true,
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id: ID_DEP,
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implicitlyLoadedAfterOneOf: [ID_MAIN1, ID_MAIN2],

‎test/chunking-form/samples/implicit-dependencies/single-dependency/_config.js‎

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@@ -68,6 +68,7 @@ module.exports = {
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dynamicallyImportedIdResolutions: [],
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dynamicallyImportedIds: [],
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dynamicImporters: [],
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hasDefaultExport: false,
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hasModuleSideEffects: true,
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id: ID_MAIN,
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implicitlyLoadedAfterOneOf: [],
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dynamicallyImportedIdResolutions: [],
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dynamicallyImportedIds: [],
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dynamicImporters: [],
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hasDefaultExport: false,
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hasModuleSideEffects: true,
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id: ID_DEP,
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implicitlyLoadedAfterOneOf: [ID_MAIN],

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