test replacing ts-jest with @swc-node/jest

[sod]

We don't use this package, but we use jest & angular and maybe you are interested.

We replaced ts-jest with @swc-node/jest. Cold cache jest went from 60s to 7s.

swc is a typescript to javascript compiler that also supports annotations & metadata export, thus works with angular jit. swc is written in rust and is ~70x faster as typescript. So by using it you eliminate the compile overhead and are mostly left running the tests themself.

using swc-jest as a jest transformer is pretty straight forward, this is our transform block in jest.config.js

    transform: {
        '\\.ts$': [
            require.resolve('@swc-node/jest'),
            {
                target: 'es2018',
                module: 'commonjs',
                experimentalDecorators: true,
                emitDecoratorMetadata: true,
                dynamicImport: true,
                sourcemap: true,
            },
        ],
    }