https://github.com/gajus/find-duplicates

Finds duplicate entries in a JavaScript array using an iteratee.
https://github.com/gajus/find-duplicates

javascript utility

Last synced: 20 days ago
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Finds duplicate entries in a JavaScript array using an iteratee.

• Host: GitHub
• URL: https://github.com/gajus/find-duplicates
• Owner: gajus
• License: other
• Created: 2018-06-29T10:47:41.000Z (over 6 years ago)
• Default Branch: master
• Last Pushed: 2020-02-05T06:31:22.000Z (almost 5 years ago)
• Last Synced: 2024-10-05T13:48:26.081Z (about 1 month ago)
• Topics: javascript, utility
• Language: JavaScript
• Size: 13.7 KB
• Stars: 8
• Watchers: 3
• Forks: 0
• Open Issues: 0
• Metadata Files:
  • Readme: README.md
  • License: LICENSE

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README

        
# find-duplicates

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Finds duplicate entries in a JavaScript array using an iteratee.

## API

```js

type DuplicatePointerType = {|

  +index: number,

  +value: T,

|};

const findDuplicates = (members: $ReadOnlyArray, iteratee: (T) => string) => $ReadOnlyArray<$ReadOnlyArray>>;

```

## Usage

`findDuplicates` produces an array of duplicate input array entries as identified using iteratee function.

```js

import findDuplicates from 'find-duplicates';

const haystack = [

  {

    id: 1,

    name: 'a'

  },

  {

    id: 2,

    name: 'b'

  },

  {

    id: 3,

    name: 'a'

  },

  {

    id: 4,

    name: 'b'

  },

  {

    id: 5,

    name: 'c'

  }

];

const duplicates = findDuplicates(haystack, (subject) => {

  return subject.name;

});

duplicates;

[

  [

    {

      index: 0,

      value: {

        id: 1,

        name: 'a'

      }

    },

    {

      index: 2,

      value: {

        id: 3,

        name: 'a'

      }

    }

  ],

  [

    {

      index: 1,

      value: {

        id: 2,

        name: 'b'

      },

    },

    {

      index: 3,

      value: {

        id: 4,

        name: 'b'

      },

    },

  ]

]

```

## Benchmark

Run benchmark before making changes and ensure that performance does not degrade after changes.

```bash

$ npm run benchmark

```