Path mapping doesn't work with modules ending in ".js"

[alexeagle]

Path mapping lets me locate most modules with *, but not those ending with .js.

Repro:

./node_modules/.bin/tsc -v
Version 2.3.2

# Put the zone.js npm package in a place other than node_modules
$ yarn add zone.js
$ mkdir other_node_modules
$ mv node_modules/zone.js other_node_modules/

$ cat index.ts
import {} from 'zone.js';
let z: Zone;

$ cat tsconfig.json
{
  "compilerOptions": {
    "target": "es5",
    "module": "commonjs",
    "baseUrl": "./",
    "traceResolution": true,
    "paths": {
      "*": [
        "other_node_modules/*"
      ]
    }
  },
  "files": [
    "index.ts"
  ]
}

$ ./node_modules/.bin/tsc
======== Resolving module 'zone.js' from '/Users/alexeagle/repro2/index.ts'. ========
Module resolution kind is not specified, using 'NodeJs'.
'baseUrl' option is set to '/Users/alexeagle/repro2/', using this value to resolve non-relative module name 'zone.js'.
'paths' option is specified, looking for a pattern to match module name 'zone.js'.
Module name 'zone.js', matched pattern '*'.
Trying substitution 'other_node_modules/*', candidate module location: 'other_node_modules/zone.js'.
File '/Users/alexeagle/repro2/other_node_modules/zone.js' does not exist.
Loading module 'zone.js' from 'node_modules' folder, target file type 'TypeScript'.
File '/Users/alexeagle/repro2/node_modules/zone.js.ts' does not exist.
File '/Users/alexeagle/repro2/node_modules/zone.js.tsx' does not exist.
File '/Users/alexeagle/repro2/node_modules/zone.js.d.ts' does not exist.
File name '/Users/alexeagle/repro2/node_modules/zone.js' has a '.js' extension - stripping it.
File '/Users/alexeagle/repro2/node_modules/zone.ts' does not exist.
File '/Users/alexeagle/repro2/node_modules/zone.tsx' does not exist.
File '/Users/alexeagle/repro2/node_modules/zone.d.ts' does not exist.
Directory '/Users/alexeagle/repro2/node_modules/@types' does not exist, skipping all lookups in it.
File name '/Users/alexeagle/repro2/node_modules/@types/zone.js' has a '.js' extension - stripping it.
Directory '/Users/alexeagle/node_modules' does not exist, skipping all lookups in it.
File name '/Users/alexeagle/node_modules/zone.js' has a '.js' extension - stripping it.
File name '/Users/alexeagle/node_modules/@types/zone.js' has a '.js' extension - stripping it.
Directory '/Users/node_modules' does not exist, skipping all lookups in it.
File name '/Users/node_modules/zone.js' has a '.js' extension - stripping it.
File name '/Users/node_modules/@types/zone.js' has a '.js' extension - stripping it.
Directory '/node_modules' does not exist, skipping all lookups in it.
File name '/node_modules/zone.js' has a '.js' extension - stripping it.
File name '/node_modules/@types/zone.js' has a '.js' extension - stripping it.
'baseUrl' option is set to '/Users/alexeagle/repro2/', using this value to resolve non-relative module name 'zone.js'.
'paths' option is specified, looking for a pattern to match module name 'zone.js'.
Module name 'zone.js', matched pattern '*'.
Trying substitution 'other_node_modules/*', candidate module location: 'other_node_modules/zone.js'.
File '/Users/alexeagle/repro2/other_node_modules/zone.js' does not exist.
Loading module 'zone.js' from 'node_modules' folder, target file type 'JavaScript'.
File '/Users/alexeagle/repro2/node_modules/zone.js.js' does not exist.
File '/Users/alexeagle/repro2/node_modules/zone.js.jsx' does not exist.
File name '/Users/alexeagle/repro2/node_modules/zone.js' has a '.js' extension - stripping it.
File '/Users/alexeagle/repro2/node_modules/zone.js' does not exist.
File '/Users/alexeagle/repro2/node_modules/zone.jsx' does not exist.
Directory '/Users/alexeagle/node_modules' does not exist, skipping all lookups in it.
File name '/Users/alexeagle/node_modules/zone.js' has a '.js' extension - stripping it.
Directory '/Users/node_modules' does not exist, skipping all lookups in it.
File name '/Users/node_modules/zone.js' has a '.js' extension - stripping it.
Directory '/node_modules' does not exist, skipping all lookups in it.
File name '/node_modules/zone.js' has a '.js' extension - stripping it.
======== Module name 'zone.js' was not resolved. ========
index.ts(2,8): error TS2304: Cannot find name 'Zone'.

As a workaround, if my tsconfig bypasses the lookup of the package.json file to point directly to the d.ts file:

    "paths": {
      "*": [
        "other_node_modules/*"
      ],
      "zone.js": [
        "other_node_modules/zone.js/dist/zone.js.d.ts"
      ]
    }

Then the program type-checks.

[DanielRosenwasser]

For context, a similar previous issue #12098.

Does this still occur if you use --allowJs?

Ah it's a directory. Thanks @mhegazy 😄

[alexeagle]

Nope, can still repro with --allowJs.