docs: Fixed incorrect docs regarding synchronous fallback for unimple… (

#14056)

CHANGELOG.md

@@ -13,6 +13,7 @@
 ### Chore & Maintenance
 
 - `[docs]` Updated documentation for the `--runTestsByPath` CLI command ([#14004](https://github.com/facebook/jest/pull/14004))
+- `[docs]` Updated documentation regarding the synchronous fallback when asynchronous code transforms are unavailable ([#14056](https://github.com/facebook/jest/pull/14056))
 
 ### Performance
 

docs/CodeTransformation.md

@@ -138,9 +138,11 @@ The definitions above were trimmed down for brevity. Full code can be found in [
 
 :::
 
-There are a couple of ways you can import code into Jest - using Common JS (`require`) or ECMAScript Modules (`import` - which exists in static and dynamic versions). Jest passes files through code transformation on demand (for instance when a `require` or `import` is evaluated). This process, also known as "transpilation", might happen _synchronously_ (in the case of `require`), or _asynchronously_ (in the case of `import` or `import()`, the latter of which also works from Common JS modules). For this reason, the interface exposes both pairs of methods for asynchronous and synchronous processes: `process{Async}` and `getCacheKey{Async}`. The latter is called to figure out if we need to call `process{Async}` at all. Since async transformation can happen synchronously without issue, it's possible for the async case to "fall back" to the sync variant, but not vice versa.
+There are a couple of ways you can import code into Jest - using Common JS (`require`) or ECMAScript Modules (`import` - which exists in static and dynamic versions). Jest passes files through code transformation on demand (for instance when a `require` or `import` is evaluated). This process, also known as "transpilation", might happen _synchronously_ (in the case of `require`), or _asynchronously_ (in the case of `import` or `import()`, the latter of which also works from Common JS modules). For this reason, the interface exposes both pairs of methods for asynchronous and synchronous processes: `process{Async}` and `getCacheKey{Async}`. The latter is called to figure out if we need to call `process{Async}` at all.
 
-So if your code base is ESM only implementing the async variants is sufficient. Otherwise, if any code is loaded through `require` (including `createRequire` from within ESM), then you need to implement the synchronous variant. Be aware that `node_modules` is not transpiled with default config.
+Asynchronous transpilation can fall back to the synchronous `process` call if `processAsync` is unimplemented, but synchronous transpilation cannot use the asynchronous `processAsync` call. If your codebase is ESM only, implementing the async variants are sufficient. Otherwise, if any code is loaded through `require` (including `createRequire` from within ESM), then you need to implement the synchronous `process` variant.
+
+Be aware that `node_modules` is not transpiled with default config, the `transformIgnorePatterns` setting must be modified in order to do so.
 
 Semi-related to this are the supports flags we pass (see `CallerTransformOptions` above), but those should be used within the transform to figure out if it should return ESM or CJS, and has no direct bearing on sync vs async
 

website/versioned_docs/version-28.x/CodeTransformation.md

@@ -138,9 +138,11 @@ The definitions above were trimmed down for brevity. Full code can be found in [
 
 :::
 
-There are a couple of ways you can import code into Jest - using Common JS (`require`) or ECMAScript Modules (`import` - which exists in static and dynamic versions). Jest passes files through code transformation on demand (for instance when a `require` or `import` is evaluated). This process, also known as "transpilation", might happen _synchronously_ (in the case of `require`), or _asynchronously_ (in the case of `import` or `import()`, the latter of which also works from Common JS modules). For this reason, the interface exposes both pairs of methods for asynchronous and synchronous processes: `process{Async}` and `getCacheKey{Async}`. The latter is called to figure out if we need to call `process{Async}` at all. Since async transformation can happen synchronously without issue, it's possible for the async case to "fall back" to the sync variant, but not vice versa.
+There are a couple of ways you can import code into Jest - using Common JS (`require`) or ECMAScript Modules (`import` - which exists in static and dynamic versions). Jest passes files through code transformation on demand (for instance when a `require` or `import` is evaluated). This process, also known as "transpilation", might happen _synchronously_ (in the case of `require`), or _asynchronously_ (in the case of `import` or `import()`, the latter of which also works from Common JS modules). For this reason, the interface exposes both pairs of methods for asynchronous and synchronous processes: `process{Async}` and `getCacheKey{Async}`. The latter is called to figure out if we need to call `process{Async}` at all.
 
-So if your code base is ESM only implementing the async variants is sufficient. Otherwise, if any code is loaded through `require` (including `createRequire` from within ESM), then you need to implement the synchronous variant. Be aware that `node_modules` is not transpiled with default config.
+Asynchronous transpilation can fall back to the synchronous `process` call if `processAsync` is unimplemented, but synchronous transpilation cannot use the asynchronous `processAsync` call. If your codebase is ESM only, implementing the async variants are sufficient. Otherwise, if any code is loaded through `require` (including `createRequire` from within ESM), then you need to implement the synchronous `process` variant.
+
+Be aware that `node_modules` is not transpiled with default config, the `transformIgnorePatterns` setting must be modified in order to do so.
 
 Semi-related to this are the supports flags we pass (see `CallerTransformOptions` above), but those should be used within the transform to figure out if it should return ESM or CJS, and has no direct bearing on sync vs async
 

website/versioned_docs/version-29.0/CodeTransformation.md

@@ -138,9 +138,11 @@ The definitions above were trimmed down for brevity. Full code can be found in [
 
 :::
 
-There are a couple of ways you can import code into Jest - using Common JS (`require`) or ECMAScript Modules (`import` - which exists in static and dynamic versions). Jest passes files through code transformation on demand (for instance when a `require` or `import` is evaluated). This process, also known as "transpilation", might happen _synchronously_ (in the case of `require`), or _asynchronously_ (in the case of `import` or `import()`, the latter of which also works from Common JS modules). For this reason, the interface exposes both pairs of methods for asynchronous and synchronous processes: `process{Async}` and `getCacheKey{Async}`. The latter is called to figure out if we need to call `process{Async}` at all. Since async transformation can happen synchronously without issue, it's possible for the async case to "fall back" to the sync variant, but not vice versa.
+There are a couple of ways you can import code into Jest - using Common JS (`require`) or ECMAScript Modules (`import` - which exists in static and dynamic versions). Jest passes files through code transformation on demand (for instance when a `require` or `import` is evaluated). This process, also known as "transpilation", might happen _synchronously_ (in the case of `require`), or _asynchronously_ (in the case of `import` or `import()`, the latter of which also works from Common JS modules). For this reason, the interface exposes both pairs of methods for asynchronous and synchronous processes: `process{Async}` and `getCacheKey{Async}`. The latter is called to figure out if we need to call `process{Async}` at all.
 
-So if your code base is ESM only implementing the async variants is sufficient. Otherwise, if any code is loaded through `require` (including `createRequire` from within ESM), then you need to implement the synchronous variant. Be aware that `node_modules` is not transpiled with default config.
+Asynchronous transpilation can fall back to the synchronous `process` call if `processAsync` is unimplemented, but synchronous transpilation cannot use the asynchronous `processAsync` call. If your codebase is ESM only, implementing the async variants are sufficient. Otherwise, if any code is loaded through `require` (including `createRequire` from within ESM), then you need to implement the synchronous `process` variant.
+
+Be aware that `node_modules` is not transpiled with default config, the `transformIgnorePatterns` setting must be modified in order to do so.
 
 Semi-related to this are the supports flags we pass (see `CallerTransformOptions` above), but those should be used within the transform to figure out if it should return ESM or CJS, and has no direct bearing on sync vs async
 

website/versioned_docs/version-29.1/CodeTransformation.md

@@ -138,9 +138,11 @@ The definitions above were trimmed down for brevity. Full code can be found in [
 
 :::
 
-There are a couple of ways you can import code into Jest - using Common JS (`require`) or ECMAScript Modules (`import` - which exists in static and dynamic versions). Jest passes files through code transformation on demand (for instance when a `require` or `import` is evaluated). This process, also known as "transpilation", might happen _synchronously_ (in the case of `require`), or _asynchronously_ (in the case of `import` or `import()`, the latter of which also works from Common JS modules). For this reason, the interface exposes both pairs of methods for asynchronous and synchronous processes: `process{Async}` and `getCacheKey{Async}`. The latter is called to figure out if we need to call `process{Async}` at all. Since async transformation can happen synchronously without issue, it's possible for the async case to "fall back" to the sync variant, but not vice versa.
+There are a couple of ways you can import code into Jest - using Common JS (`require`) or ECMAScript Modules (`import` - which exists in static and dynamic versions). Jest passes files through code transformation on demand (for instance when a `require` or `import` is evaluated). This process, also known as "transpilation", might happen _synchronously_ (in the case of `require`), or _asynchronously_ (in the case of `import` or `import()`, the latter of which also works from Common JS modules). For this reason, the interface exposes both pairs of methods for asynchronous and synchronous processes: `process{Async}` and `getCacheKey{Async}`. The latter is called to figure out if we need to call `process{Async}` at all.
 
-So if your code base is ESM only implementing the async variants is sufficient. Otherwise, if any code is loaded through `require` (including `createRequire` from within ESM), then you need to implement the synchronous variant. Be aware that `node_modules` is not transpiled with default config.
+Asynchronous transpilation can fall back to the synchronous `process` call if `processAsync` is unimplemented, but synchronous transpilation cannot use the asynchronous `processAsync` call. If your codebase is ESM only, implementing the async variants are sufficient. Otherwise, if any code is loaded through `require` (including `createRequire` from within ESM), then you need to implement the synchronous `process` variant.
+
+Be aware that `node_modules` is not transpiled with default config, the `transformIgnorePatterns` setting must be modified in order to do so.
 
 Semi-related to this are the supports flags we pass (see `CallerTransformOptions` above), but those should be used within the transform to figure out if it should return ESM or CJS, and has no direct bearing on sync vs async
 

website/versioned_docs/version-29.2/CodeTransformation.md

@@ -138,9 +138,11 @@ The definitions above were trimmed down for brevity. Full code can be found in [
 
 :::
 
-There are a couple of ways you can import code into Jest - using Common JS (`require`) or ECMAScript Modules (`import` - which exists in static and dynamic versions). Jest passes files through code transformation on demand (for instance when a `require` or `import` is evaluated). This process, also known as "transpilation", might happen _synchronously_ (in the case of `require`), or _asynchronously_ (in the case of `import` or `import()`, the latter of which also works from Common JS modules). For this reason, the interface exposes both pairs of methods for asynchronous and synchronous processes: `process{Async}` and `getCacheKey{Async}`. The latter is called to figure out if we need to call `process{Async}` at all. Since async transformation can happen synchronously without issue, it's possible for the async case to "fall back" to the sync variant, but not vice versa.
+There are a couple of ways you can import code into Jest - using Common JS (`require`) or ECMAScript Modules (`import` - which exists in static and dynamic versions). Jest passes files through code transformation on demand (for instance when a `require` or `import` is evaluated). This process, also known as "transpilation", might happen _synchronously_ (in the case of `require`), or _asynchronously_ (in the case of `import` or `import()`, the latter of which also works from Common JS modules). For this reason, the interface exposes both pairs of methods for asynchronous and synchronous processes: `process{Async}` and `getCacheKey{Async}`. The latter is called to figure out if we need to call `process{Async}` at all.
 
-So if your code base is ESM only implementing the async variants is sufficient. Otherwise, if any code is loaded through `require` (including `createRequire` from within ESM), then you need to implement the synchronous variant. Be aware that `node_modules` is not transpiled with default config.
+Asynchronous transpilation can fall back to the synchronous `process` call if `processAsync` is unimplemented, but synchronous transpilation cannot use the asynchronous `processAsync` call. If your codebase is ESM only, implementing the async variants are sufficient. Otherwise, if any code is loaded through `require` (including `createRequire` from within ESM), then you need to implement the synchronous `process` variant.
+
+Be aware that `node_modules` is not transpiled with default config, the `transformIgnorePatterns` setting must be modified in order to do so.
 
 Semi-related to this are the supports flags we pass (see `CallerTransformOptions` above), but those should be used within the transform to figure out if it should return ESM or CJS, and has no direct bearing on sync vs async
 

website/versioned_docs/version-29.3/CodeTransformation.md

@@ -138,9 +138,11 @@ The definitions above were trimmed down for brevity. Full code can be found in [
 
 :::
 
-There are a couple of ways you can import code into Jest - using Common JS (`require`) or ECMAScript Modules (`import` - which exists in static and dynamic versions). Jest passes files through code transformation on demand (for instance when a `require` or `import` is evaluated). This process, also known as "transpilation", might happen _synchronously_ (in the case of `require`), or _asynchronously_ (in the case of `import` or `import()`, the latter of which also works from Common JS modules). For this reason, the interface exposes both pairs of methods for asynchronous and synchronous processes: `process{Async}` and `getCacheKey{Async}`. The latter is called to figure out if we need to call `process{Async}` at all. Since async transformation can happen synchronously without issue, it's possible for the async case to "fall back" to the sync variant, but not vice versa.
+There are a couple of ways you can import code into Jest - using Common JS (`require`) or ECMAScript Modules (`import` - which exists in static and dynamic versions). Jest passes files through code transformation on demand (for instance when a `require` or `import` is evaluated). This process, also known as "transpilation", might happen _synchronously_ (in the case of `require`), or _asynchronously_ (in the case of `import` or `import()`, the latter of which also works from Common JS modules). For this reason, the interface exposes both pairs of methods for asynchronous and synchronous processes: `process{Async}` and `getCacheKey{Async}`. The latter is called to figure out if we need to call `process{Async}` at all.
 
-So if your code base is ESM only implementing the async variants is sufficient. Otherwise, if any code is loaded through `require` (including `createRequire` from within ESM), then you need to implement the synchronous variant. Be aware that `node_modules` is not transpiled with default config.
+Asynchronous transpilation can fall back to the synchronous `process` call if `processAsync` is unimplemented, but synchronous transpilation cannot use the asynchronous `processAsync` call. If your codebase is ESM only, implementing the async variants are sufficient. Otherwise, if any code is loaded through `require` (including `createRequire` from within ESM), then you need to implement the synchronous `process` variant.
+
+Be aware that `node_modules` is not transpiled with default config, the `transformIgnorePatterns` setting must be modified in order to do so.
 
 Semi-related to this are the supports flags we pass (see `CallerTransformOptions` above), but those should be used within the transform to figure out if it should return ESM or CJS, and has no direct bearing on sync vs async
 

website/versioned_docs/version-29.4/CodeTransformation.md

@@ -138,9 +138,11 @@ The definitions above were trimmed down for brevity. Full code can be found in [
 
 :::
 
-There are a couple of ways you can import code into Jest - using Common JS (`require`) or ECMAScript Modules (`import` - which exists in static and dynamic versions). Jest passes files through code transformation on demand (for instance when a `require` or `import` is evaluated). This process, also known as "transpilation", might happen _synchronously_ (in the case of `require`), or _asynchronously_ (in the case of `import` or `import()`, the latter of which also works from Common JS modules). For this reason, the interface exposes both pairs of methods for asynchronous and synchronous processes: `process{Async}` and `getCacheKey{Async}`. The latter is called to figure out if we need to call `process{Async}` at all. Since async transformation can happen synchronously without issue, it's possible for the async case to "fall back" to the sync variant, but not vice versa.
+There are a couple of ways you can import code into Jest - using Common JS (`require`) or ECMAScript Modules (`import` - which exists in static and dynamic versions). Jest passes files through code transformation on demand (for instance when a `require` or `import` is evaluated). This process, also known as "transpilation", might happen _synchronously_ (in the case of `require`), or _asynchronously_ (in the case of `import` or `import()`, the latter of which also works from Common JS modules). For this reason, the interface exposes both pairs of methods for asynchronous and synchronous processes: `process{Async}` and `getCacheKey{Async}`. The latter is called to figure out if we need to call `process{Async}` at all.
 
-So if your code base is ESM only implementing the async variants is sufficient. Otherwise, if any code is loaded through `require` (including `createRequire` from within ESM), then you need to implement the synchronous variant. Be aware that `node_modules` is not transpiled with default config.
+Asynchronous transpilation can fall back to the synchronous `process` call if `processAsync` is unimplemented, but synchronous transpilation cannot use the asynchronous `processAsync` call. If your codebase is ESM only, implementing the async variants are sufficient. Otherwise, if any code is loaded through `require` (including `createRequire` from within ESM), then you need to implement the synchronous `process` variant.
+
+Be aware that `node_modules` is not transpiled with default config, the `transformIgnorePatterns` setting must be modified in order to do so.
 
 Semi-related to this are the supports flags we pass (see `CallerTransformOptions` above), but those should be used within the transform to figure out if it should return ESM or CJS, and has no direct bearing on sync vs async