Maintain src/ folder structure when building to dist/ folder with Typescript 3

Question

I have a TypeScript nodejs server with this structure:

tsconfig.json
package.json
src/
    middleware/
    utils/
    index.ts
dist/
    middleware/
    utils/
    index.js

When using TypeScript 2, I was able to transpile my project from the src/ to a dist/ folder and have a mirror image of my directory structure to work with.

With the release of TypeScript 3, they have introduced project references and changed the way code is transpiled into an output directory. Now tsc outputs to the dist/ folder in a nested way like this:

dist/
    src/
        middleware/
        utils/
        index.js

My tsconfig.json is:

{
  "compilerOptions": {
    "target": "es5",
    "module": "commonjs",
    "moduleResolution": "node",
    "allowJs": true,
    "emitDecoratorMetadata": true,
    "experimentalDecorators": true,
    "resolveJsonModule": true,
    "declaration": false,
    "outDir": "dist/",
    "lib": [
      "es7",
      "dom"
    ]
  },
  "include": [
    "src/"
  ]
}

How can I configure TypeScript to output my src/ folder as a mirror image into a dist/ folder?

Answer 1

I had a similar problem when initially converting to a TypeScript project. I also set resolveJsonModule: true and the src directory was copied to the output dist directory.

The underlying reason is that one of my source files required package.json at the root of the project. Once I removed that, tsc no longer added src to the dist directory.

In short, make sure you are not requiring files outside of your src directory.

Explanatory FAQ here: https://github.com/Microsoft/TypeScript/wiki/FAQ#why-does---outdir-moves-output-after-adding-a-new-file

Answer 2

The structure of the output directory is controlled by the rootDir of the compilerOptions. See documentation here, setting it to ./src should solve the issue.

{
  "compilerOptions": {
    "rootDir": "src",
    ...
  },
  "include": [
    "src/"
  ]
}