Be lazy, write simple tests in comments.

✅ VS Code - flawlessly works in Problems panel.

⏹ Sublime Text - could not get it to work but it might be possible.

❔ Atom - not tested.

⛔ tsc - plugins are disabled during build. It should work with webpack ts loader.

npm install typescript-expect-plugin

1. Add plugin to tsconfig.json:

{
  "compilerOptions": {
    "plugins": [{ "name": "typescript-expect-plugin" }]
  },
}

2. Change VS Code typescript to workspace version:

⚠Tests are executed after each file change - not save. Be careful if you're going to test functions that remove or change files in your local system

This plugin adds support for @expect JSDoc tag. It has the following usage pattern:

/**
 * @expect [PARAMS] CONDITION CONDITION_PARAMETER
 */

• [PARAMS] - for example [2, 4] will spread two arguments to tested function.
• CONDITION - check function from jest expect library. Use ctrl space to see autocomplete suggestions.
• CONDITION_PARAMETER - argument passed to CONDITION function.

/**
 * @expect [2, 4] toBe 6
 * @expect [2, 2] toBeGreaterThan 3
 * @expect [2, 2] toBeLessThan 3
 * @expect [2, 22] toEqual 24
 */
export function sum(a: number, b: number) {
  return a   b;
}

/**
 * @expect [[2, 4, 8], 4] toBeTruthy
 * @expect [[2, 4, 8], 12] toBeFalsy
 */
export function has(haystack: any[], needle: any) {
  return haystack.includes(needle);
}

/**
 * @expect [[2, 8], [9, 12]] toEqual [2, 8, 9, 12]
 */
export function join(arr1: any[], arr2: any[]) {
  return [...arr1, ...arr2];
}

/**
 * @expect [{"firstName": "John"}, "lastName", "Doe"] toHaveProperty "lastName", "Doe Doe"
 */
export function withProp(obj: Record<string, any>, key: string, value: any) {
  return {...obj, [key]: value}
}

Test objects

Test arrays

Hey there, I'm Kasper. If you wish to get notified about more cool typescript or react projects/tips you can follow me on twitter.