How to merge duplicate values in array of objects

Question

I have an array of objects and I have duplicated value on it and I want to merge all duration who have been created in the same date and who have the same file Name

Thank You In Advance :)

I have array of objects

[
    {
    fileName: "test.js"
    duration: 1500,
    createt_at: "2019-07-26T09:57:28.126Z"
    },
    {
    fileName: "test.js"
    duration: 1500,
    createt_at: "2019-07-26T10:00:28.126Z"
    },
    {
    fileName: "test.js"
    duration: 1500,
    createt_at: "2019-07-26T09:57:28.126Z"
    },
    {
    fileName: "main.js"
    duration: 1500,
    createt_at: "2019-07-26T09:57:28.126Z"
    },
    {
    fileName: "main.js"
    duration: 3000,
    createt_at: "2019-07-28T10:57:28.126Z"
    },
    {
    fileName: "main.js"
    duration: 2000,
    createt_at: "2019-07-28T11:00:28.126Z"
    }
    {
    fileName: "main.js"
    duration: 100,
    createt_at: "2019-07-28T09:00:28.126Z"
    }
]

Output Array Of Objects Need To Be Like This :

[
    {
    fileName: "test.js"
    duration: 3000,
    createt_at: "2019-07-26"
    },
    {
    fileName: "main.js"
    duration: 1500,
    createt_at: "2019-07-26"
    },
    {
    fileName: "main.js"
    duration: 5100,
    createt_at: "2019-07-28"
    }
]

You should try to use reduce on your array. [MDN](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/Reduce) — Quinox, Jul 28 '19 at 10:42
@quino I tried to filter and reduce array but I didn't get what I want — Ilias haddad, Jul 28 '19 at 10:53

Code Maniac · Accepted Answer · 2019-07-28T10:55:09.037

You can use fileName and date as combined key and add duration accordingly

Loop through array, check if combined key is present on Map or not
If not present initialize it with current element's value,
If already present then add duration of current element with the value of particular key

let data = [{fileName: "test.js",duration: 1500,createt_at: "2019-07-26T09:57:28.126Z"},{fileName: "test.js",duration: 1500,createt_at: "2019-07-26T10:00:28.126Z"},{fileName: "test.js",duration: 1500,createt_at: "2019-07-26T09:57:28.126Z"},{fileName: "main.js",duration: 1500,createt_at: "2019-07-26T09:57:28.126Z"},{fileName: "main.js",duration: 3000,createt_at: "2019-07-28T10:57:28.126Z"},{fileName: "main.js",duration: 2000,createt_at: "2019-07-28T11:00:28.126Z"}, {fileName: "main.js",duration: 100,createt_at: "2019-07-28T09:00:28.126Z"}]


let op = data.reduce((op,inp) => {
  let {fileName,createt_at} = inp
  let date = createt_at.substring(0,10)
  let key = fileName+date
  if(op.has(key)){
    let val = op.get(key)
    val.duration += inp.duration
  } else {
    op.set(key,inp)
  }
  return op
},new Map())

console.log([...op.values()])

Nice! Could you please explain the meaning of `let {fileName,createt_at} = inp`? — Reza Saadati, Jul 28 '19 at 11:08
@RezaSaadati thanks, this is called [`destructuring`](https://stackoverflow.com/questions/54605286/what-is-destructuring-assignment-and-its-uses), i am using this to take `fileName and createt_at` properties form object — Code Maniac, Jul 28 '19 at 11:10

How to merge duplicate values in array of objects

1 Answers1