WASM components within dependencies are most often built

outside of the regular Node.js `make build` step. They also

require different tools.

It is important that the tools and their versions used to build

WASM components shipped within Node.js are well documented and

be available if needed to rebuild/update older Node.js versions.

In order to minimize the different number of tools and versions

used to build WASM components and to document and ensure future

availability, the project builds and maintains a common

[wasm-builder](https://github.com/nodejs/wasm-builder) container

that should be use to build WASM components in Node.js

dependencies.

The container provides a durable copy of the versions of the tools

used for a specific build which are under the control of the Node.js

project. In addition, the tools and verions are documented through metadata

within the container in the `/home/node/metadata directory`.

The available tools can be found by looking at the current version of the

[Dockerfile](https://github.com/nodejs/wasm-builder/blob/main/container-build-info/Dockerfile)

used to create the container.

If additional WASM tool are needed beyond those available in the

container, additions should be PR'd into the wasm-builder container.

Examples of using the container include:

* [build/wasm.js](https://github.com/nodejs/undici/blob/main/build/wasm.js) from undici

* [tools/build-wasm.js](https://github.com/nodejs/amaro/blob/main/tools/build-wasm.js) from amaro

In addition to using the container to build WASM components, the goal is also

for the WASM components and final files that are shipped with Node.js to be

built by the [dep-updaters](https://github.com/nodejs/node/tree/main/tools/dep_updaters)

that are run on a regular basis and that they use only the files available in the Node.js

repo for the dependency. For example, being able to rebuild the WASM and files that

we ship in Node.js using only the files in

[../deps/undici](https://github.com/nodejs/node/tree/main/deps/undici).