Tsc-checkjs is proof-of-concept Javascript typechecker using Typescript compiler API to ignore errors and warnings generated by dependencies.
Following sections explain installation, usage of the commmand and reasoning why this is needed.
Install the package
npm install --save-dev tsc-checkjs
tsc-checkjs <LIST OF FILES>- or
npx tsc-checkjs <LIST OF FILES>
Note: only small subset of tsc command line arguments works properly with tsc-typecheck.
Working:
- compiler related flags: e.g.
--noImplicitAnyand--strictNullChecks
Not working:
-p- build related flags
Typescript FAQ(1) states following:
to do so, the compiler needs the definition of a module, this could be a .ts file for your own code, or a .d.ts for an imported definition file. If the file was found, it will be included regardless of whether it was excluded in the previous steps or not.
So to exclude a file from the compilation, you need to exclude both the file itself and all files that have an import or /// directive to it.
In some cases unwanted errors and warnings are generated from dependencies when using tsc for Javascript typechecking.
Running tsc --noImplicitAny -p jsconfig.json in test/ex folder gives following output:
index.js:3:14 - error TS2554: Expected 0 arguments, but got 1.
3 testdata.foo(1)
~
node_modules/tsc-checkjs-broken-dep/index.js:3:5 - error TS2322: Type '"1"' is not assignable to type 'number'.
3 a = '1'
~
Found 2 errors.
Compiler includes node_modules/tsc-checkjs-broken-dep/index.js as dependency and checks it causing unwanted error message.
The PoC code calls Typescript via compiler API and filters out errors of dependencies. Running node ../../index.js index.js in test/ex folder outputs following:
index.js:3:14 - error TS2554: Expected 0 arguments, but got 1.
3 testdata.foo(1)
~
Found 1 errors.
Filtered out 1 error entries.
Process exiting with code '1'.
Error caused by node_modules/tsc-checkjs-broken-dep/index.js:3:5 is being filtered out.
Current code is modified from Typescript API example(2).
--pretty--skipGlob
- Proper CLI with arguments
- configurable ignore string(s) to ignore other dependency folders than node_modules
- support
-p, support more build flags if needed, reporter type selection - reporter selection. (works automatically now)
- [jt]sconfig.json support with
-p
Copyright 2020 jikuja
Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:
The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.
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(2) https://github.com/Microsoft/TypeScript/wiki/Using-the-Compiler-API