The [cjs-module-lexer](https://github.com/nodejs/node/tree/HEAD/deps/cjs-module-lexer)

dependency is used within the Node.js ESM implementation to detect the

named exports of a CommonJS module.

It is used within

in which both `internal/deps/cjs-module-lexer/lexer` and

`internal/deps/cjs-module-lexer/dist/lexer` are required and used.

is a regular JavaScript implementation that is

used when WebAssembly is not available on a platform.

`internal/deps/cjs-module-lexer/dist/lexer` is a faster

implementation using WebAssembly which is generated from a

C based implementation. These two paths

resolve to the files in `deps/cjs-module-lexer` due to their

inclusion in the `deps_files` entry in

[node.gyp](https://github.com/nodejs/node/blob/master/node.gyp).

The two different versions of lexer.js are maintained in the

[nodejs/cjs-module-lexer][] project.

In order to update the Node.js dependencies to use to a newer verion

of cjs-module-lexer, complete the following steps:

* Clone [nodejs/cjs-module-lexer][]

and check out the version that you want Node.js to use.

* Follow the WASM build steps outlined in

[wasm-build-steps](https://github.com/nodejs/cjs-module-lexer#wasm-build-steps).

This will generate the WASM based dist/lexer.js file.

* Preserving the same directory structure, copy the following files over

to `deps/cjs-module-lexer` directory where you have checked out Node.js.

* Update the link to the cjs-module-lexer in the list at the end of

[doc/api/esm.md](../api/esm.md)

to point to the updated version.

* Create a PR, adding the files in the deps/cjs-module-lexer that

were modified.

If updates are needed to cjs-module-lexer for Node.js, first PR

those updates into

[nodejs/cjs-module-lexer][],

request a release and then pull in the updated version once available.

[nodejs/cjs-module-lexer]: https://github.com/nodejs/cjs-module-lexer