https://github.com/zhangchiqing/simple-pair
simple pair implementation in Javascript
https://github.com/zhangchiqing/simple-pair
Last synced: 4 months ago
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simple pair implementation in Javascript
- Host: GitHub
- URL: https://github.com/zhangchiqing/simple-pair
- Owner: zhangchiqing
- License: mit
- Created: 2016-10-02T03:50:34.000Z (over 8 years ago)
- Default Branch: master
- Last Pushed: 2016-12-16T17:59:47.000Z (over 8 years ago)
- Last Synced: 2025-02-09T12:34:50.730Z (5 months ago)
- Language: JavaScript
- Size: 5.86 KB
- Stars: 0
- Watchers: 2
- Forks: 0
- Open Issues: 1
-
Metadata Files:
- Readme: README.md
- License: LICENSE
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README
# simple-pairs
simple pair implementation in Javascript
# Usage
```javascript
// [User]
var users = [
{ id: 1, name: 'userA' },
{ id: 2, name: 'userB' },
{ id: 3, name: 'userC' },
];
// [Photo]
var photos = [
{ userId: 1, photo: ' :) ' },
{ userId: 3, photo: ' :( ' },
{ userId: 2, photo: ' :-) ' },
{ userId: 2, photo: ' :-/ ' },
];
var Pair = require('simple-pair').Pair;
var Pairs = require('simple-pair').Pairs;
var R = require('ramda');
// Photo -> User? -> PhotoWithUser
var makePhotoWithUserName = function(photo, user) {
return {
userId: photo.userId,
username: user ? user.name : null,
photo: photo.photo,
};
};
var indexer = function(
idIndex, // User -> UserId
photoIndex, // Photo -> String
users, // [User]
photos, // [Photo]
makePhotoWithUserName // Photo -> User? -> PhotoWithUser
) { // [PhotoWithUser]
// Map UserId User
var indexMap = R.indexOf(idIndex, users);
return R.map(function(p) {
// UserId
var userId = photoIndex.userId;
// User?
var user = indexMap[userId];
return makePhotoWithUserName(p, user);
}, photos);
};
// [{ userId: UserId, photo: String, name: String }]
var photosWithMap = indexer(
R.prop('id'),
R.prop('id'),
users,
photos,
makePhotoWithUserName
);
```
# API
```haskell
Pair.make :: a -> b -> Pair a b
Pair.first :: Pair a b -> a
Pair.second :: Pair a b -> b
Pair.mapFirst :: (a -> c) -> Pair a b -> Pair c b
Pair.mapSecond :: (b -> c) -> Pair a b -> Pair a c
Pair.swap :: Pair a b -> Pair b a
Pairs.fromMap :: Map a b -> [Pair a b]
Pairs.toMap :: [Pair a b] -> Map a b
```