Replace alias paths with relative paths after typescript compilation. You can add aliases that reference other projects outside your tsconfig.json project by providing a relative path to the baseUrl.

+ Compile time (no runtime dependencies)

First, install tsc-alias as devDependency using npm.

npm install -g tsc-alias

npm install --save-dev tsc-alias

"scripts": {
  "build": "tsc --project tsconfig.json && tsc-alias -p tsconfig.json",
}

================ OR ===================

"scripts": {
  "build": "tsc && tsc-alias",
  "build:watch": "concurrently \"tsc -w\" \"tsc-alias -w\""
}

npm install tsc-alias

import { replaceTscAliasPaths } from 'tsc-alias';

replaceTscAliasPaths(options?);

Here are all the available options:

{
  "compilerOptions": {
    ...
  },
  "tsc-alias": {
    "verbose": false,
    "resolveFullPaths": true,
    "replacers": {
      "exampleReplacer": {
        "enabled": true,
        "file": "./exampleReplacer.js"
      },
      "otherReplacer": {
        "enabled": true,
        "file": "./otherReplacer.js"
      }
    }
  }
}

We can use tsc-alias in a single file, with a function that returns the modified contents.

We prepare the replacer with prepareSingleFileReplaceTscAliasPaths(), passing the same options that we would pass to replaceTscAliasPaths(). That will return a promise of a function that receives the file contents and path, and returns the transformed contents, synchronously.

import { prepareSingleFileReplaceTscAliasPaths } from 'tsc-alias';

const runFile: SingleFileReplacer = await prepareSingleFileReplaceTscAliasPaths(options?);

function treatFile(filePath: string) {
  const fileContents = fs.readFileSync(filePath, 'utf8');
  const newContents = runFile({fileContents, filePath});
  // do stuff with newContents
}