group-array

group-array

Group array of objects into lists.

Table of Contents

• Install
• Usage
• Examples
• About

(TOC generated by verb using markdown-toc)

Install

Install with npm:

$ npm install --save group-array

Usage

var groupArray = require('group-array');

Examples

var arr = [
  {tag: 'one', content: 'A'},
  {tag: 'one', content: 'B'},
  {tag: 'two', content: 'C'},
  {tag: 'two', content: 'D'},
  {tag: 'three', content: 'E'},
  {tag: 'three', content: 'F'}
];

// group by the `tag` property
groupArray(arr, 'tag');

results in:

{
  one: [
    {tag: 'one', content: 'A'},
    {tag: 'one', content: 'B'}
  ],
  two: [
    {tag: 'two', content: 'C'},
    {tag: 'two', content: 'D'}
  ],
  three: [
    {tag: 'three', content: 'E'},
    {tag: 'three', content: 'F'}
  ]
}

Group by multiple, deeply nested properties

// given an array of object, like blog posts...
var arr = [
  { data: { year: '2016', tag: 'one', month: 'jan', day: '01'}, content: '...'},
  { data: { year: '2016', tag: 'one', month: 'jan', day: '01'}, content: '...'},
  { data: { year: '2016', tag: 'one', month: 'jan', day: '02'}, content: '...'},
  { data: { year: '2016', tag: 'one', month: 'jan', day: '02'}, content: '...'},
  { data: { year: '2016', tag: 'one', month: 'feb', day: '10'}, content: '...'},
  { data: { year: '2016', tag: 'one', month: 'feb', day: '10'}, content: '...'},
  { data: { year: '2016', tag: 'one', month: 'feb', day: '12'}, content: '...'},
  { data: { year: '2016', tag: 'one', month: 'feb', day: '12'}, content: '...'},
  { data: { year: '2016', tag: 'two', month: 'jan', day: '14'}, content: '...'},
  { data: { year: '2016', tag: 'two', month: 'jan', day: '14'}, content: '...'},
  { data: { year: '2016', tag: 'two', month: 'jan', day: '16'}, content: '...'},
  { data: { year: '2016', tag: 'two', month: 'jan', day: '16'}, content: '...'},
  { data: { year: '2016', tag: 'two', month: 'feb', day: '18'}, content: '...'},
  { data: { year: '2017', tag: 'two', month: 'feb', day: '18'}, content: '...'},
  { data: { year: '2017', tag: 'two', month: 'feb', day: '10'}, content: '...'},
  { data: { year: '2017', tag: 'two', month: 'feb', day: '10'}, content: '...'},
  { data: { year: '2017', tag: 'three', month: 'jan', day: '01'}, content: '...'},
  { data: { year: '2017', tag: 'three', month: 'jan', day: '01'}, content: '...'},
  { data: { year: '2017', tag: 'three', month: 'jan', day: '02'}, content: '...'},
  { data: { year: '2017', tag: 'three', month: 'jan', day: '02'}, content: '...'},
  { data: { year: '2017', tag: 'three', month: 'feb', day: '01'}, content: '...'},
  { data: { year: '2017', tag: 'three', month: 'feb', day: '01'}, content: '...'},
  { data: { year: '2017', tag: 'three', month: 'feb', day: '02'}, content: '...'},
  { data: { year: '2017', tag: 'three', month: 'feb', day: '02'}, content: '...'}
]

Pass a list or array of properties:

groupArray(arr, 'data.year', 'data.tag', 'data.month', 'data.day');

Results in something like this: (abbreviated)

{ '2016': 
   { one: 
      { jan: 
         { '01': 
            [ { data: { year: '2016', tag: 'one', month: 'jan', day: '01' },
                content: '...' },
              { data: { year: '2016', tag: 'one', month: 'jan', day: '01' },
                content: '...' } ],
           '02': 
            [ { data: { year: '2016', tag: 'one', month: 'jan', day: '02' },
                content: '...' },
              { data: { year: '2016', tag: 'one', month: 'jan', day: '02' },
                content: '...' } ] },
        feb: 
         { '10': 
            [ { data: { year: '2016', tag: 'one', month: 'feb', day: '10' },
                content: '...' },
              { data: { year: '2016', tag: 'one', month: 'feb', day: '10' },
                content: '...' } ],
           '12': 
            [ { data: { year: '2016', tag: 'one', month: 'feb', day: '12' },
                content: '...' },
              { data: { year: '2016', tag: 'one', month: 'feb', day: '12' },
                content: '...' } ] } },
     two: 
      { jan: 
         { '14': 
            [ { data: { year: '2016', tag: 'two', month: 'jan', day: '14' },
                content: '...' },
              { data: { year: '2016', tag: 'two', month: 'jan', day: '14' },
                content: '...' } ],
           '16': 
            [ { data: { year: '2016', tag: 'two', month: 'jan', day: '16' },
                content: '...' },
              { data: { year: '2016', tag: 'two', month: 'jan', day: '16' },
                content: '...' } ] },
        feb: 
         { '18': 
            [ { data: { year: '2016', tag: 'two', month: 'feb', day: '18' },
                content: '...' } ] } } },
  '2017': 
   { two: 
      { feb: 
         { '10': 
            [ { data: { year: '2017', tag: 'two', month: 'feb', day: '10' },
                content: '...' },
              { data: { year: '2017', tag: 'two', month: 'feb', day: '10' },
                content: '...' } ],
           '18': 
            [ { data: { year: '2017', tag: 'two', month: 'feb', day: '18' },
                content: '...' } ] } },
     three: 
      { jan: 
         { '01': 
            [ { data: { year: '2017', tag: 'three', month: 'jan', day: '01' },
                content: '...' },
              { data: { year: '2017', tag: 'three', month: 'jan', day: '01' },
                content: '...' } ],
           '02': 
            [ { data: { year: '2017', tag: 'three', month: 'jan', day: '02' },
                content: '...' },
              { data: { year: '2017', tag: 'three', month: 'jan', day: '02' },
                content: '...' } ] },
        feb: 
         { '01': 
            [ { data: { year: '2017', tag: 'three', month: 'feb', day: '01' },
                content: '...' },
              { data: { year: '2017', tag: 'three', month: 'feb', day: '01' },
                content: '...' } ],
           '02': 
            [ { data: { year: '2017', tag: 'three', month: 'feb', day: '02' },
                content: '...' },
              { data: { year: '2017', tag: 'three', month: 'feb', day: '02' },
                content: '...' } ] } } } }

About

Related projects

• arr-flatten: Recursively flatten an array or arrays. This is the fastest implementation of array flatten. | homepage
• get-value: Use property paths (a.b.c) to get a nested value from an object. | homepage
• group-object: Group object keys and values into lists. | homepage
• union-value: Set an array of unique values as the property of an object. Supports setting deeply… more | homepage

Contributing

Pull requests and stars are always welcome. For bugs and feature requests, please create an issue.

Contributors

Commits	Contributor
23	doowb
6	jonschlinkert
1	cperryk

Building docs

(This project's readme.md is generated by verb, please don't edit the readme directly. Any changes to the readme must be made in the .verb.md readme template.)

To generate the readme, run the following command:

$ npm install -g verbose/verb#dev verb-generate-readme && verb

Running tests

Running and reviewing unit tests is a great way to get familiarized with a library and its API. You can install dependencies and run tests with the following command:

$ npm install && npm test

Author

Brian Woodward

• github/doowb
• twitter/doowb

License

Copyright © 2017, Brian Woodward. Released under the MIT License.

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This file was generated by verb-generate-readme, v0.4.2, on February 24, 2017.