🔥 TypeScript type assertion plugin for vitest

Related tags

Learning resource typescript test assert type-checking assertion expect type-check vite vitest
Overview

TypeScript type assertion plugin for vitest.

vite-plugin-vitest-typescript-assert : TypeScript assertion (test) plugin for vitest

📌 This plugin is in alpha version, and will probably stay that way for a long time, it lacks tests (a bit ironic) and real documentation! But I can't stop myself from publishing it. Moreover this plugin is a succession of tricks to integrate it to vitest (it would be incredible that vitest offer an official plugin system 💜 ). But it seems to work for my use cases and maybe for you too? I'm thinking of continuing to evolve it if I need it or if others start using it. Feel free to contribute or give feedback if you encounter any issues. Thank you.

Installation

Install the dependencies.

pnpm add -D vitest typescript vite-plugin-vitest-typescript-assert
# yarn and npm also works

Setup the plugin in vitest.config.ts file.

import { defineConfig } from 'vite';
import { vitestTypescriptAssertPlugin } from 'vite-plugin-vitest-typescript-assert';

export default defineConfig({
  plugins: [vitestTypescriptAssertPlugin()],
});

Assertions APIs

This plugin was more than inspired by the tsd project, much of the assertion logic comes from their code.

That's why two APIs are available:

// Exactly the same behaviour as tsd (plus any bugs I might have introduced 🙈)
import * as tsd from 'vite-plugin-vitest-typescript-assert/tsd';
// A more descriptive/flexible API with some additions.
import * as tssert from 'vite-plugin-vitest-typescript-assert/tssert';

Named imports, alias imports and named exports are supported in both API.

import { expectType } from 'vite-plugin-vitest-typescript-assert/tsd';
import { expectType as assertType } from 'vite-plugin-vitest-typescript-assert/tsd';

export { expectType as assertType } from 'vite-plugin-vitest-typescript-assert/tsd';

tsd docs

expectType<ExpectedType>(value);
expectNotType<ExpectedType>(value);
expectAssignable<ExpectedType>(value);
expectNotAssignable<ExpectedType>(value);
expectError(value);
expectDeprecated(expression);
expectNotDeprecated(expression);
printType(expression);

tssert

tssert supports 4 signatures for each method. You can either specify the type in the generic or the value in the first argument, but never both at the same time. But don't worry, if this happens the plugin will send you an error.

expectType<string>().assignableTo<string>();
expectType<string>().assignableTo('nyan');
expectType('nyan').assignableTo<string>();
expectType('nyan').assignableTo('nyan');
expectType<ExpectedType>().assignableTo(value);
expectType<ExpectedType>().identicalTo(value);
expectType<ExpectedType>().subtypeOf(value);
expectType<ExpectedType>().equalTo(value);
expectType<ExpectedType>().toBeDeprecated();
expectType<ExpectedType>().toThrowError();
expectType<ExpectedType>().toThrowError(code);
expectType<ExpectedType>().toThrowError(message);

expectType<ExpectedType>().not.assignableTo(value);
expectType<ExpectedType>().not.identicalTo(value);
expectType<ExpectedType>().not.subtypeOf(value);
expectType<ExpectedType>().not.equalTo(value);
expectType<ExpectedType>().not.toBeDeprecated();

Options

vitestTypescriptAssertPlugin(options?: PluginOptions);

By default the plugin applies the following configuration.

const defaultOptions: PluginOptions = {
  report: ['type-error', 'type-assertion'],
  include: ['**/*.test.ts'],
  exclude: [],
  typescript: {
    configName: 'tsconfig.json',
    searchPath: process.cwd(),
    compilerOptions: {},
  },
};
  • type-error: Report the errors raised by the TS compiler.
  • type-assertion: Report the errors raised by the assertion library.
export interface PluginOptions {
  report?: 'type-error' | 'type-assertion';
  include?: string | string[];
  exclude?: string | string[];
  typescript?: TypeScriptConfigOptions;
}

interface TypeScriptConfigOptions {
  configName?: string;
  searchPath?: string;
  compilerOptions?: ts.CompilerOptions;
}

Contributing 💜

See CONTRIBUTING.md

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Comments
  • Reported errors don't agree with TypeScript IDE / CLI

    Reported errors don't agree with TypeScript IDE / CLI

    Describe the bug

    CleanShot 2022-09-05 at 17 10 33@2x

    In the above you can see that the reported error is not reported in the IDE and I know it to be correct (e.g. this would pass in Jest before etc.).

    Reproduction

    Run tests on this branch https://github.com/jasonkuhrt/alge/tree/tests/try-vite-ts-plugin

    System Info

    Node 18, vitest 0.23

    Used Package Manager

    pnpm

    Validations

    • [X] Follow our Code of Conduct
    • [X] Read the Contributing Guide.
    • [X] Check that there isn't already an issue that reports the same bug to avoid creating a duplicate.
    • [X] Check that this is a concrete bug. For Q&A, please open a GitHub Discussion instead.
    • [X] The provided reproduction is a minimal reproducible of the bug.
    bug 
    opened by jasonkuhrt 7
  • ESM support

    ESM support

    When using this plugin in a project specifying "type": "module" in its package.json, no tests can be run due to the following error:

    import { isMatch } from "micromatch";
         ^^^^^^^
SyntaxError: Named export 'isMatch' not found. The requested module 'micromatch' is a CommonJS module, which may not support all module.exports as named exports.
CommonJS modules can always be imported via the default export, for example using:

import pkg from 'micromatch';
const { isMatch } = pkg;

    You can find a repro of the issue in this repository.

    released 
    opened by HiDeoo 2
  • `esModuleInterop` support

    `esModuleInterop` support

    When using this plugin in a project not specifying in its tsconfig.json the esModuleInterop option or setting it to false, no tests can be run due to the following error:

    FAIL  index.test.ts [ index.test.ts ]
TypeError: Module '"chai"' has no exported member 'default'.

    You can find a repro of the issue in this repository.

    released 
    opened by HiDeoo 2
Releases(v1.1.4)
Owner
In JavaScript We Trust // Mangeur de code
null
GitHub https://www.npmjs.com/package/vite-plugin-vitest-typescript-assert
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