Add retriable dynamic imports behind a feature flag (#9860)

* import retries * cache result if succesful
parcel-bundler · Jul 23, 2024 · 3054d8c · 3054d8c
1 parent ae96448
commit 3054d8c
Show file tree

Hide file tree

Showing 5 changed files with 50 additions and 0 deletions.
diff --git a/packages/core/core/test/test-utils.js b/packages/core/core/test/test-utils.js
@@ -55,6 +55,7 @@ export const DEFAULT_OPTIONS: ParcelOptions = {
  featureFlags: {
  exampleFeature: false,
  parcelV3: false,
+ importRetry: false,
  },
 };
 

diff --git a/packages/core/feature-flags/src/index.js b/packages/core/feature-flags/src/index.js
@@ -8,6 +8,7 @@ export type FeatureFlags = _FeatureFlags;
 export const DEFAULT_FEATURE_FLAGS: FeatureFlags = {
  exampleFeature: false,
  parcelV3: false,
+ importRetry: false,
 };
 
 let featureFlagValues: FeatureFlags = {...DEFAULT_FEATURE_FLAGS};

diff --git a/packages/core/feature-flags/src/types.js b/packages/core/feature-flags/src/types.js
@@ -7,4 +7,8 @@ export type FeatureFlags = {|
  * Rust backed requests
  */
  +parcelV3: boolean,
+ /**
+ * Configure runtime to enable retriable dynamic imports
+ */
+ importRetry: boolean,
 |};
diff --git a/packages/runtimes/js/src/JSRuntime.js b/packages/runtimes/js/src/JSRuntime.js
@@ -484,6 +484,24 @@ function getLoaderRuntime({
  )}'))`;
  }
 
+ if (needsEsmLoadPrelude && options.featureFlags.importRetry) {
+ loaderCode = `
+ Object.defineProperty(module, 'exports', { get: () => {
+ let load = require('./helpers/browser/esm-js-loader-retry');
+ return ${loaderCode}.then((v) => {
+ Object.defineProperty(module, "exports", { value: Promise.resolve(v) })
+ return v
+ });
+ }})`;
+
+ return {
+ filePath: __filename,
+ code: loaderCode,
+ dependency,
+ env: {sourceType: 'module'},
+ };
+ }
+
  let code = [];
 
  if (needsEsmLoadPrelude) {

diff --git a/packages/runtimes/js/src/helpers/browser/esm-js-loader-retry.js b/packages/runtimes/js/src/helpers/browser/esm-js-loader-retry.js
@@ -0,0 +1,26 @@
+async function load(id) {
+ if (!parcelRequire.retryState) {
+ parcelRequire.retryState = {};
+ }
+
+ if (!globalThis.navigator.onLine) {
+ await new Promise(res =>
+ globalThis.addEventListener('online', res, {once: true}),
+ );
+ }
+
+ let url = require('../bundle-manifest').resolve(id);
+
+ if (parcelRequire.retryState[id] != undefined) {
+ url = `${url}?retry=${parcelRequire.retryState[id]}`;
+ }
+
+ try {
+ // eslint-disable-next-line no-undef
+ return await __parcel__import__(url);
+ } catch (error) {
+ parcelRequire.retryState[id] = Date.now();
+ }
+}
+
+module.exports = load;