fix(plugin-legacy): bake-in Promise polyfill, fix vitejs#4414 (vitejs…

…#4440)
aleclarson · Nov 8, 2021 · 3a51d6c · 3a51d6c
1 parent c502bcf
commit 3a51d6c
Showing 1 changed file with 6 additions and 1 deletion.
diff --git a/packages/plugin-legacy/index.js b/packages/plugin-legacy/index.js
@@ -44,7 +44,12 @@ function viteLegacyPlugin(options = {}) {
   const facadeToLegacyPolyfillMap = new Map()
   const facadeToModernPolyfillMap = new Map()
   const modernPolyfills = new Set()
-  const legacyPolyfills = new Set()
+  // System JS relies on the Promise interface. It needs to be polyfilled for IE 11. (array.iterator is mandatory for supporting Promise.all)
+  const DEFAULT_LEGACY_POLYFILL = [
+    'core-js/modules/es.promise',
+    'core-js/modules/es.array.iterator'
+  ]
+  const legacyPolyfills = new Set(DEFAULT_LEGACY_POLYFILL)
 
   if (Array.isArray(options.modernPolyfills)) {
     options.modernPolyfills.forEach((i) => {