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https://github.com/kylecorbelli/typescript-pattern-match
Pattern Matching with More Complex Scrutinees
https://github.com/kylecorbelli/typescript-pattern-match
Last synced: about 1 month ago
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Pattern Matching with More Complex Scrutinees
- Host: GitHub
- URL: https://github.com/kylecorbelli/typescript-pattern-match
- Owner: kylecorbelli
- Created: 2018-05-10T16:20:56.000Z (over 6 years ago)
- Default Branch: master
- Last Pushed: 2018-05-10T22:24:25.000Z (over 6 years ago)
- Last Synced: 2024-09-19T06:18:49.626Z (3 months ago)
- Language: TypeScript
- Size: 47.9 KB
- Stars: 8
- Watchers: 2
- Forks: 0
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
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README
# TypeScript Pattern Match
[](https://circleci.com/gh/kylecorbelli/typescript-pattern-match)
[](https://codecov.io/gh/kylecorbelli/typescript-pattern-match)
## What is This?
A type-safe way to pattern match on more than just a single value. Think pattern matching on tuples.
## Installation
In your terminal:
```
$ npm install --save typescript-pattern-match
```
In your TypeScript files:
```TypeScript
import { patternMatch } from 'typescript-pattern-match'
```
## API
Think of it like a more powerful `switch` statement.
```
patternMatch :: (scrutinee: A, cases: ReadonlyArray>, defaultBlock: () => B): B
```
The `scrutinee` is the value you’re trying to match against. The `cases` are similar to the list of `case` statements in a standard `switch` block and are passed in as an array to `patternMatch`. Each case block must have a `.case` value and a `.do` function. `patternMatch` will invoke and return the return value of the `.do` function associated with the first `.case` value to match the `scrutinee`. There is no fallthrough.
The third and final argument passed to `patternMatch` is a function whose return value is the default value returned if none of the `cases` match the `scrutinee`.
## Example Usage
We can now match on type-safe tuples!
```TypeScript
patternMatch([ true, 'noob noob' ], [
{
case: [ true, 'MPB' ],
do: () => 'oooo weee!',
},
{
case: [ false, 'noob noob' ],
do: () => 'this guy gets it',
},
{
case: [ true, 'noob noob' ],
do: () => {
console.log('you can perform calculations or do whatever here')
return 'this is the matched case'
},
},
], () => {
return 'the default'
})
```