{"patch":"diff --git a\/packages\/react-refresh\/src\/ReactFreshRuntime.js b\/packages\/react-refresh\/src\/ReactFreshRuntime.js\nindex 24f434702e..2ccfe7eece 100644\n--- a\/packages\/react-refresh\/src\/ReactFreshRuntime.js\n+++ b\/packages\/react-refresh\/src\/ReactFreshRuntime.js\n@@ -21,14 +21,22 @@ type Signature = {|\n getCustomHooks: () => Array,\n |};\n \n+\/\/ In old environments, we'll leak previous types after every edit.\n+const PossiblyWeakMap = typeof WeakMap === 'function' ? WeakMap : Map;\n+const PossiblyWeakSet = typeof WeakSet === 'function' ? WeakSet : Set;\n+\n \/\/ We never remove these associations.\n \/\/ It's OK to reference families, but use WeakMap\/Set for types.\n const allFamiliesByID: Map = new Map();\n-const allTypes: WeakSet = new WeakSet();\n-const allSignaturesByType: WeakMap = new WeakMap();\n+\/\/ $FlowIssue\n+const allTypes: WeakSet | Set = new PossiblyWeakSet();\n+const allSignaturesByType: \/\/ $FlowIssue\n+WeakMap | Map = new PossiblyWeakMap();\n \/\/ This WeakMap is read by React, so we only put families\n \/\/ that have actually been edited here. This keeps checks fast.\n-const familiesByType: WeakMap = new WeakMap();\n+\/\/ $FlowIssue\n+const familiesByType: \/\/ $FlowIssue\n+WeakMap | Map = new PossiblyWeakMap();\n \n \/\/ This is cleared on every prepareUpdate() call.\n \/\/ It is an array of [Family, NextType] tuples.\n","parents":["a3c5b1fb8bca787eaeef2f39a72920ea03da179c"],"body":"* Fall back to Map\/Set if Weak equivalents are not available\r\n\r\n* Fix Prettier vs Flow fighting","commit":{"authorName":"Dan Abramov","revision":"cd98e63b47198147cfd140cd4454a6db68e08a9f","authoredAt":"2019-06-17T16:00:29+01:00","subject":"[Fresh] Fall back to Map\/Set if Weak equivalents are not available (#15907)","authorEmail":"dan.abramov@gmail.com","shortRevision":"cd98e63b47"},"files":[{"status":"M","path":"packages\/react-refresh\/src\/ReactFreshRuntime.js"}]}

dillon1000/react

Files changed