Compatibility with yarn workspaces pnp

[Downchuck]

Jest has added compatibility to resolve yarn pnp projects, but it seems ts-jest is not compatible as it is unable to find typescript. This can be worked around for now by just disabling pnp: yarn install --disable-pnp

perhaps needs https://github.com/arcanis/ts-pnp

[ahnpnl]

Close as duplicate #1333 and related to monorepo support in #1336

[ahnpnl]

ts-jest doesn't use compiler host, are there any ways else to tackle this ?

[darioblanco]

I don't know for sure if it is 100% related to this issue, but I managed to run ts-jest in a monorepo-based yarn2 PnP project.

Steps:

• Do not use moduleNameMapper as stated in the migration guide. I instead use the link protocol in package.json, linking the package to "itself".
• Do not use the preset config in Jest. Instead, I have used transform directly like this:

  transform: {
    '.(ts|tsx)': require.resolve('ts-jest'),
  },

Besides the ts-jest[config] (WARN) Unable to find the root of the project where ts-jest has been installed., everything seems to work now for a basic project.

I use ts-node 8.5.4 and jest 25.1.0