tsconfig-paths crashes when `compilerOptions` is not present

To reproduce:

tsconfig.json:

{
  "extends": "../../tsconfig.json",
}

Now I run: "test": "mocha --no-timeouts --compilers ts:ts-node/register -r tsconfig-paths/register 'tests/index.ts'"

And get:

/home/whoeverest/freelance/99abcproj/my-work-project/node_modules/tsconfig-paths/lib/tsconfig-loader.js:17
        baseUrl: loadResult.config.compilerOptions.baseUrl,
                                                  ^
TypeError: Cannot read property 'baseUrl' of undefined
    at loadSyncDefault (/home/whoeverest/freelance/99abcproj/my-work-project/node_modules/tsconfig-paths/lib/tsconfig-loader.js:17:51)
    at tsConfigLoader (/home/whoeverest/freelance/99abcproj/my-work-project/node_modules/tsconfig-paths/lib/tsconfig-loader.js:8:22)
    at Object.configLoader (/home/whoeverest/freelance/99abcproj/my-work-project/node_modules/tsconfig-paths/lib/config-loader.js:18:22)
    at Object.register (/home/whoeverest/freelance/99abcproj/my-work-project/node_modules/tsconfig-paths/lib/register.js:9:46)
    at Object.<anonymous> (/home/whoeverest/freelance/99abcproj/my-work-project/node_modules/tsconfig-paths/register.js:1:15)
    at Module._compile (module.js:573:30)
    at Object.Module._extensions..js (module.js:584:10)
    at Module.load (module.js:507:32)
    at tryModuleLoad (module.js:470:12)
    at Function.Module._load (module.js:462:3)
    at Module.require (module.js:517:17)
    at require (internal/module.js:11:18)
    at /home/whoeverest/freelance/99abcproj/my-work-project/node_modules/mocha/bin/_mocha:345:3
    at Array.forEach (<anonymous>)
    at Object.<anonymous> (/home/whoeverest/freelance/99abcproj/my-work-project/node_modules/mocha/bin/_mocha:344:10)
    at Module._compile (module.js:573:30)
    at Object.Module._extensions..js (module.js:584:10)
    at Module.load (module.js:507:32)
    at tryModuleLoad (module.js:470:12)
    at Function.Module._load (module.js:462:3)
    at Function.Module.runMain (module.js:609:10)
    at startup (bootstrap_node.js:158:16)
    at bootstrap_node.js:598:3

If I add compilerOptions to tsconfig.json it works. This doesn’t crash:

{
  "extends": "../../tsconfig.json",
  "compilerOptions": {
    "outDir": "./build"
  }
}

Then I get a warning: Missing baseUrl in compilerOptions. tsconfig-paths will be skipped

I’m not very familiar with this tool, but it’s obvious that it tries to read from compilerOptions which in this case is undefined. Hope it makes sense.

---

EDIT: BTW, there is a baseUrl defined in the top-level tsconfig.json which the local one extends. Is that a bug, too?

[jonaskello]

Yes, we are using the tsconfig package to read the tsconfig.json file. The tsconfig.json file is not 100% json. For example it allows for comments which the json standard does not. I think submitting a PR for the issue mentioned above would be the best solution.

[wh4everest]

I have set paths and baseUrl in the main tsconfig.json from which I extend:

{
  "compilerOptions": {
    "sourceMap": true,
    "sourceRoot": ".",
    "...": "...",
    "baseUrl": "./",
    "paths": {
      "*": ["packages/*/src"]
    },
    "plugins": ["..."]
}

I think some part of the library code parses the derived tsconfig.json, assumes that compilerOptions is present on the object (when trying to check if baseUrl is present) and throws the exception “Cannot read property ‘baseUrl’ of undefined”.

A totally blind guess: some check somewhere needs to look like this: obj.compilerOptions && obj.compilerOptions.baseUrl 😃