https://github.com/zhangchiqing/join-by-index

A function that joins two arrays with index fields
https://github.com/zhangchiqing/join-by-index

Last synced: 2 months ago
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A function that joins two arrays with index fields

• Host: GitHub
• URL: https://github.com/zhangchiqing/join-by-index
• Owner: zhangchiqing
• License: mit
• Created: 2016-11-19T15:57:28.000Z (over 8 years ago)
• Default Branch: master
• Last Pushed: 2016-11-22T22:36:39.000Z (over 8 years ago)
• Last Synced: 2024-10-14T13:18:35.833Z (9 months ago)
• Language: JavaScript
• Homepage:
• Size: 2.93 KB
• Stars: 6
• Watchers: 2
• Forks: 0
• Open Issues: 0
• Metadata Files:
  • Readme: README.md
  • License: LICENSE

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README

        
# join-by-index

A function that joins two arrays with index fields

## Usage:

```javascript

var R = require('ramda');

var joinByIndex = require('join-by-index');

// [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: ' :-/ ' },

  { userId: 4, photo: ' :-)) ' },

];

// (User?, Photo) -> PhotoWithUserName

var makePhotoWithUserName = function(user, photo) {

  return {

    userId: photo.userId,

    username: user ? user.name : null,

    photo: photo.photo,

  };

};

// [PhotoWithUserName]

var photosWithUserName = joinByIndex(

  R.prop('id'),

  R.prop('userId'),

  makePhotoWithUserName,

  users,

  photos

);

console.log(photosWithUserName);

// [

//   { userId: 1, photo: ' :) ', username: 'userA' },

//   { userId: 3, photo: ' :( ', username: 'userC' },

//   { userId: 2, photo: ' :-) ', username: 'userB' },

//   { userId: 2, photo: ' :-/ ', username: 'userB' },

//   { userId: 4, photo: ' :-)) ', username: null },

// ]

```

## API

```

joinByIndex :: (a -> c) -> (b -> c) -> (a?, b) -> d -> [a] -> [b] -> [d]

```