rust-crypto is included by default which leads to bundle size growth

[ms-dosx86]

Reproduction: https://github.com/ms-dosx86/matrix-js-sdk-example

Steps to reproduce:

1. npm i
2. ng build

An empty project with just createClient() weighs 8.89mb.

You can also do ng build --stats-json and upload dist/matrix-js-sdk-example/stats.json to https://esbuild.github.io/analyze/ to see what causes such huge bundle size.

This happens because of lazy rust-crypto import here

https://github.com/matrix-org/matrix-js-sdk/blob/develop/src/client.ts#L2255

it looks fine, the source of problem is babel preset module: 'commonjs'

https://github.com/matrix-org/matrix-js-sdk/blob/develop/.babelrc#L10

which makes the lazy import not quite lazy.

Possible workaround for those who is facing the same problem:

1. Clone matrix-js-sdk
2. Set module: false and node: 18 in .babelrc
3. Replace this line https://github.com/matrix-org/matrix-js-sdk/blob/develop/src/models/MSC3089TreeSpace.ts#L38 with import type { EncryptedFile, FileContent } from "../@types/media";
4. yarn build
5. Copy lib and replace with it node_modules/matrix-js-sdk/lib.

[richvdh]

I'm afraid I'm not following everything you're saying here; I'm not that familiar with all the finer details of babel and the javascript ecosystem, and I've never used ng.

It does seem a problem that the transpiled js-sdk forces the rust-crypto import to be resolved at load time. (We don't encounter this in element-web because we use the typescript source in src, rather than the transpiled code in lib.) And yes, it seems like we need to change the module setting.

A couple of questions about your solution:

Set module: false and node: 18 in .babelrc

I think updating node makes sense, but I don't entirely follow why it is necessary here. Please could you explain?

3. Replace this line https://github.com/matrix-org/matrix-js-sdk/blob/develop/src/models/MSC3089TreeSpace.ts#L38 with import type { EncryptedFile, FileContent } from "../@types/media";

Again, I don't understand why this is necessary. Are you saying that importing @types/media somehow adds a dependency on matrix-sdk-crypto? How so?

[ms-dosx86]

Hi @richvdh ! I was trying to hotfix the problem, so don't take this workaround seriously as a solution.

1. You're right, setting node: 18 is not necessary, only need to set modules: false to preserve ESM.
2. The reason why I added import type there is because my attempt to build matrix-js-sdk locally failed. For some reason tsc didn't remove those interface imports. There are no interfaces at runtime hence there is nothing to import from "../@types/media" and build attempts fail. import type forces tsc to get rid of such imports at build time. This is probably just a misconfiguration error and should not be considered as necessary as well.

[richvdh]

Why don't you open a PR setting modules: false and we can discuss further on it?

[ms-dosx86]

@richvdh Sure. Here is a PR