Combine duplicate values by date in JavaScript array

August 30, 2022

Good afternoon, I need some help to combine the data of this example array taking the position [0] of the date and the position [1] of the name (AA, BB, CC…)

//Origin Array
[
['10/08/2022',  'AA',   '08:00',    '12:00',    '',       '17:00'],
['10/08/2022',  'BB',   '08:01',    '13:15',    '14:16',    '17:01'],
['10/08/2022',  'AA',   ''     ,    ''     ,  '13:00',  ''     ],
['10/08/2022',  'CC',   '09:00',    '11:30',    '12:30',    '18:00']
]

//Result Array
[
['10/08/2022',  'AA',   '08:00',    '12:00',    '13:00',    '17:00'],
['10/08/2022',  'BB',   '08:01',    '13:15',    '14:16',    '17:01'],
['10/08/2022',  'CC',   '09:00',    '11:30',    '12:30',    '18:00']
]

>Solution :

You can use reduce method to group the items, and checkValue will combine the filled values only, and Object.values to return it to a multi diminution array after object reduction.

const data = [
['10/08/2022',  'AA',   '08:00',    '12:00',    '',       '17:00'],
['10/08/2022',  'BB',   '08:01',    '13:15',    '14:16',    '17:01'],
['10/08/2022',  'AA',   ''     ,    ''     ,  '13:00',  ''     ],
['10/08/2022',  'CC',   '09:00',    '11:30',    '12:30',    '18:00']
]

const checkValue = (oldItem, newItem) => 
    oldItem ? oldItem.map((item, i) => item || newItem[i]) : newItem

const result = Object.values(data.reduce((acc, item) => 
    ({ ...acc, [item[1]]: checkValue(acc[item[1]], item) }), 
{}))

console.log(result)