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Mofei Zhang
78856eff76
(note: also see alternative implementation in https://github.com/facebook/react/pull/32747) `PruneHoistedContexts` currently strips hoisted declarations and rewrites the first `StoreContext` reassignment to a declaration. For example, in the following example, instruction 0 is removed while a synthetic `DeclareContext let` is inserted before instruction 1. ```js // source const cb = () => x; // reference that causes x to be hoisted let x = 4; x = 5; // React Compiler IR [0] DeclareContext HoistedLet 'x' ... [1] StoreContext reassign 'x' = 4 [2] StoreContext reassign 'x' = 5 ``` Currently, we don't account for `DeclareContext let`. As a result, we're rewriting to insert duplicate declarations. For the below example, we should only remove instruction 0 (no need to insert a DeclareContext `let` since one is already present). ```js // source const cb = () => x; // reference that causes x to be hoisted let x; x = 5; // React Compiler IR [0] DeclareContext HoistedLet 'x' ... [1] DeclareContext Let 'x' [2] StoreContext reassign 'x' = 5 ```
babel-plugin-react-compiler
React Compiler is a compiler that optimizes React applications, ensuring that only the minimal parts of components and hooks will re-render when state changes. The compiler also validates that components and hooks follow the Rules of React.
This package contains the React Compiler Babel plugin use in projects that make use of Babel. You can find instructions for using this plugin here: https://react.dev/learn/react-compiler