getGroupedByProperty<T>(
      property: string,
      objects: T[],
      matchFound? = (a, b) => String(a) === String(b)
): Array<T[]>

Returns objects divided into sub-arrays, grouped by matching value of property.
The original objects array is not modified.
You can customize how a match is determined with optional callback matchFound(a, b)
(by default it returns String(a) === String(b) ).
Based on the data type of objects[0][property], this function decides how to sort
all objects. That type must be either number (sorting will be numeric), string or
boolean (sorting will be alphabetical for both). After sorting, adjacent objects are
grouped together if matchFound(a, b) returns true.

Note: property is a string that can include dot-notation ( i.e.,
'property.subproperty.subsubproperty' ). Even if property is an array index,
here you need to use dot-notation and not square braces, i.e., '1.0' // instead of [1][0]

Examples

persons = [
    {person: {hair: 'red', name: 'tom'}},
    {person: {hair: 'brown', name: 'ron'}},
    {person: {hair: 'black', name: 'harry'}},
    {person: {hair: 'blue', name: 'barry'}},
    {person: {hair: 'brown', name: 'midge'}},
    {person: {hair: 'black', name: 'sandy'}}
];
getGroupedByProperty('person.hair', persons);
/*************
Returns:
[
   [ {person: {hair: 'black', name: 'harry'}}, {person: {hair: 'black', name: 'sandy'}} ],
   [ {person: {hair: 'blue', name: 'barry'}} ],
   [ {person: {hair: 'brown', name: 'ron'}}, {person: {hair: 'brown', name: 'midge'}} ],
   [ {person: {hair: 'red', name: 'tom'}} ]
]
*************/


// If any values are null or undefined, they will be treated as if they
// were strings 'null' and 'undefined':

persons = [
    {person: {hair: 'red', name: 'tom'}},
    {person: {hair: 'null', name: 'ron'}},
    {person: {name: 'harry'}}, // missing property means its value is undefined.
    {person: {hair: null, name: 'midge'}},
    {person: {hair: undefined, name: 'sandy'}}
];
getGroupedByProperty('person.hair', persons);
/*************
Returns:
[
   [ {person: {hair: 'null', name: 'ron'}}, {person: {hair: null, name: 'midge'}} ],
   [ {person: {hair: 'red', name: 'tom'}} ],
   [ {person: {name: 'harry'}}, {person: {hair: undefined, name: 'sandy'}} ]
]
*************/


// group together arrays with the same number of items:

let arrays = [
    [1, 2], [3, 4, 5, 6, 7], [8, 9, 10], [11, 12], 
    [13, 14, 15, 16], [17, 18, 19, 20, 21], [22, 23, 24, 25]
];
getGroupedByProperty('length', arrays);
/*************
Returns:
[
   [ [1, 2], [11, 12] ],
   [ [8, 9, 10] ],
   [ [13, 14, 15, 16], [22, 23, 24, 25] ],
   [ [3, 4, 5, 6, 7], [17, 18, 19, 20, 21] ]
]
*************/


// By default, matching is case-sensitive:

objs = [{prop: 'V'}, {prop: 'v'}, {prop: 'V'}, {prop: 'A'}, {prop: 'a'}, {prop: 'a'}];
getGroupedByProperty('prop', objs);
/*************
Returns:
[
   [ { prop: 'A' } ],
   [ { prop: 'a' }, { prop: 'a' } ],
   [ { prop: 'V' }, { prop: 'V' } ],
   [ { prop: 'v' } ]
]
 *************/

// Make matching case-insensitive:
objs = [{prop: 'V'}, {prop: 'v'}, {prop: 'V'}, {prop: 'A'}, {prop: 'a'}, {prop: 'a'}];
getGroupedByProperty(
    'prop', objs, (a, b) => String(a).toLowerCase() === String(b).toLowerCase()
);
/************
Returns:
[
  [ { prop: 'A' }, { prop: 'a' }, { prop: 'a' } ],
  [ { prop: 'V' }, { prop: 'V' }, { prop: 'v' } ]
]
*************/


// These last 2 examples show the different ordering of results based on what object
// comes first in the array.

// Since the value of objs[0]['prop'] is a number, groups will be ordered
// numerically:
objs = [{prop: 1}, {prop: '1.0001'}, {prop: '2.0'}, {prop: '1'}, 
        {prop: '00100'}, {prop: '03'}];
getGroupedByProperty('prop', objs);
/***************
Returns:
[
   [ { prop: 1 }, { prop: '1' } ],
   [ { prop: '1.0001' } ],
   [ { prop: '2.0' } ],
   [ { prop: '03' } ],
   [ { prop: '00100' } ]
]
***************/

// Since the value of objs[0]['prop'] is a string, groups will be ordered
// alphabetically:
objs = [{prop: '1.0001'}, {prop: 1}, {prop: '2.0'}, {prop: '1'}, 
        {prop: '00100'}, {prop: '03'}];
getGroupedByProperty('prop', objs);
/***************
Returns:
[
   [ { prop: '00100' } ],
   [ { prop: '03' } ],
   [ { prop: 1 }, { prop: '1' } ],
   [ { prop: '1.0001' } ],
   [ { prop: '2.0' } ]
]
***************/

Installation

npm i @writetome51/get-grouped-by-property

Loading

import {getGroupedByProperty} from '@writetome51/get-grouped-by-property';