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Joe Savona
7455473e3a
Adds a `@enableNameAnonymousFunctions` feature to infer helpful names for anonymous functions within components and hooks. The logic is inspired by a custom Next.js transform, flagged to us by @eps1lon, that does something similar. Implementing this transform within React Compiler means that all React (Compiler) users can benefit from more helpful names when debugging.
The idea builds on the fact that JS engines try to infer helpful names for anonymous functions (in stack traces) when those functions are accessed through an object property lookup:
```js
({'a[xyz]': () => {
throw new Error('hello!')
} }['a[xyz]'])()
// Stack trace:
Uncaught Error: hello!
at a[xyz] (<anonymous>:1:26) // <-- note the name here
at <anonymous>:1:60
```
The new NameAnonymousFunctions transform is gated by the above flag, which is off by default. It attemps to infer names for functions as follows:
First, determine a "local" name:
* Assigning a function to a named variable uses the variable name. `const f = () => {}` gets the name "f".
* Passing the function as an argument to a function gets the name of the function, ie `foo(() => ...)` get the name "foo()", `foo.bar(() => ...)` gets the name "foo.bar()". Note the parenthesis to help understand that it was part of a call.
* Passing the function to a known hook uses the name of the hook, `useEffect(() => ...)` uses "useEffect()".
* Passing the function as a JSX prop uses the element and attr name, eg `<div onClick={() => ...}` uses "<div>.onClick".
Second, the local name is combined with the name of the outer component/hook, so the final names will be strings like `Component[f]` or `useMyHook[useEffect()]`.
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.
More information about the design and architecture of the compiler are covered in the Design Goals.
More information about developing the compiler itself is covered in the Development Guide.