https://github.com/peerigon/typescript-exercises-tools
Tools for writing and validating TypeScript exercises
https://github.com/peerigon/typescript-exercises-tools
assertions comments testing typescript typings validation
Last synced: 11 months ago
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Tools for writing and validating TypeScript exercises
- Host: GitHub
- URL: https://github.com/peerigon/typescript-exercises-tools
- Owner: peerigon
- License: unlicense
- Created: 2019-10-23T13:26:57.000Z (over 6 years ago)
- Default Branch: main
- Last Pushed: 2024-06-25T21:03:55.000Z (about 2 years ago)
- Last Synced: 2025-08-08T20:55:23.201Z (11 months ago)
- Topics: assertions, comments, testing, typescript, typings, validation
- Language: TypeScript
- Homepage:
- Size: 2.13 MB
- Stars: 0
- Watchers: 12
- Forks: 1
- Open Issues: 1
-
Metadata Files:
- Readme: README.md
- Changelog: CHANGELOG.md
- License: LICENSE
Awesome Lists containing this project
README
# @peerigon/typescript-exercises-tools
**Tools for writing and validating TypeScript exercises.**
[](https://www.npmjs.com/package/@peerigon/typescript-exercises-tools)
[](https://www.npmjs.com/package/@peerigon/typescript-exercises-tools)
[](https://david-dm.org/peerigon/@peerigon/typescript-exercises-tools)
[](https://travis-ci.com/peerigon/@peerigon/typescript-exercises-tools)
[](https://coveralls.io/github/peerigon/typescript-exercises-tools?branch=master)
[](https://snyk.io/test/github/peerigon/typescript-exercises-tools)
This module allows you to annotate expected type errors in your TypeScript code like this:
```ts
export const add = (a: number, b: string) => {
return a + b;
};
// 💥 Expect error 2345: Argument of type '4' is not assignable to parameter of type...
add(3, 4);
```
With the TypeScript language service plugin provided by this module, these expected type errors will show up as a suggestion instead of an error:
Furthermore, these comments will cause the editor to show an error if there is _no type error_ at this location:
At the time of writing, only editors use TypeScript language service plugins. Calling `tsc` from the command line will not execute the plugin. That's why there is also a programmatic API that allows you to do assertions on the program:
```ts
import { assertProgramToOnlyHaveExpectedErrors } from "@peerigon/typescript-exercises-tools/tests";
test("The program has only expected errors", () => {
assertProgramToOnlyHaveExpectedErrors("/path/to/module.ts");
});
```
This module is ideal for:
- testing types by doing assertions on the behavior of types
- creating TypeScript exercises
## Installation
```
npm install @peerigon/typescript-exercises-tools
```
Now you need to add the TypeScript language service plugin to your `tsconfig.json`:
```json
{
"compilerOptions": {
"plugins": [
{
"name": "@peerigon/typescript-exercises-tools"
}
]
}
}
```
**Please note that you need to configure your editor to use your local TypeScript version.** Otherwise TypeScript may not find the plugin. If you're using VSCode, create a file in your repository at `.vscode/settings.json` and add this:
```json
{
"typescript.tsdk": "node_modules/typescript/lib"
}
```
## API
### assertProgramToOnlyHaveExpectedErrors(
programPath: string,
compilerOptions?: ts.CompilerOptions,
): void
Compiles the program at the given `programPath` and throws the first unexpected error it encounters. It's recommended to use an absolute path. If you don't pass any `compilerOptions` to this function, it uses TypeScript's internal `findConfigFile()` to locate the closest `tsconfig.json` to `programPath`.
```ts
import { assertProgramToOnlyHaveExpectedErrors } from "@peerigon/typescript-exercises-tools/tests";
assertProgramToOnlyHaveExpectedErrors("/path/to/module.ts"); // may throw
assertProgramToOnlyHaveExpectedErrors(
"/path/to/module.ts",
{ strict: true }, // custom compiler options
);
```
## License
Unlicense
## Sponsors
[
](https://peerigon.com)