@crbroughton/ts-test-utils
v0.7.0
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A collection of testing helper types
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ts-test-utils
A collection of helper TypeScript types to test other TypeScript types. This collection so far includes:
- Expect - The main helper; Use this with the below types
- Equals - Check for equality between two types
- Assignable - Check if one type is assignable to another type
- Excludes - Check if a type doesn't contain another type
- Includes - Check if a type includes another type
- Extends - Check if one type is extending another type
- IsArray - Checks if a type is an array
- IsNotArray - Checks if a type is not an array
- Length - Check a given types length; Combine this with the 'Equals' type checker
- Position - Returns a type in the given position of an array; Combine this with the 'Equals' type checker
- IsNullable - Check if a type is nullable
- IsNonNullable - Check if a type is not nullable
- IsUndefined - Check if a type is undefined
- IsNonUndefined - Check if a type is not undefined
- IsNullish - Check if a type is either undefined or null
- IsNonNullish - Check if a type is neither undefined or null
- IsVoid - Check if a type is void
- IsNonVoid - Check if a type is not void
- NonVoid - Remove void from a union that contains void
- isUnionEqual - Check for equality between two unions
Installation
To install ts-test-utils
with Bun, run the following command:
bun i -D @crbroughton/ts-test-utils
Getting Started
You can use these types to test other types:
// This should return true
type Result = Expect<Equals<{ id: number }, { id: number }>>
For testing types that are expected to not equal each-other, you can
add the //@ts-expect-error
comment to tell the TypeScript compiler
that a false
return is expected, and that a match is not expected:
// @ts-expect-error - Object / Record failing the equality checker
type ResultRecord = Expect<Equals<{ id: number }, { id: string }>>
You can combine these types with existing types. As an example, here is the 'Equals' type being used to check a functions return type:
function myFunction() {
return {
id: 1,
name: 'Craig',
}
}
type Result = Expect<Equals<ReturnType<typeof myFunction>, { id: number, name: string }>>
Development Installation
To install dependencies:
bun install
To run:
bun run index.ts
This project was created using bun init
in bun v1.1.3. Bun is a fast all-in-one JavaScript runtime.