Javascript : Merge All Array into one

Question

I have an array of arrays which I want to marge into one and remove duplicate values.

let arr = [ {
  label :'XYZ',
  colors:['black','white','blue']
},
{
  label :'PQR',
  colors:['orange','yellow','white']
},

{
  label :'ABC',
  colors:['black','pink','blue']
},
]

let updatedArr = []


for(let i=0 i< arr.length ; i++ ){
  updatedArr.push(
                arr[i].reduce((a, b) => [...a, ...b], [])
            )

}

I want all the colors array value into one array and remove duplicate values as well.

Any help would be great.

Sebastian Speitel · Accepted Answer · 2020-05-02 11:29:31Z

1

To get a concatenated list of all values you can use flatMap(). And to deduplicate you can use [...new Set(duplicates)], which creates a Set of unique elements and spreads it into an array.

let arr = [{
    label: 'XYZ',
    colors: ['black', 'white', 'blue']
  },
  {
    label: 'PQR',
    colors: ['orange', 'yellow', 'white']
  },

  {
    label: 'ABC',
    colors: ['black', 'pink', 'blue']
  },
]

let colors = [...new Set(arr.flatMap(obj => obj.colors))]
console.log(colors)

answered May 2, 2020 at 11:29

Sebastian Speitel

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Comments

brk · Accepted Answer · 2020-05-02 11:30:29Z

0

You can use reduce and forEach. Inside reduce call back use forEach to iterate the colors array & if accumulator does not include the color then push that color to accumulator

let arr = [{
    label: 'XYZ',
    colors: ['black', 'white', 'blue']
  },
  {
    label: 'PQR',
    colors: ['orange', 'yellow', 'white']
  },

  {
    label: 'ABC',
    colors: ['black', 'pink', 'blue']
  },
]


let mergedColor = arr.reduce((acc, curr) => {
  curr.colors.forEach((item) => {
    if (acc.indexOf(item) === -1) {
      acc.push(item)
    }
  })

  return acc;
}, []);

console.log(mergedColor)

answered May 2, 2020 at 11:30

brk

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Comments

Amir Popovich · Accepted Answer · 2020-05-02 11:31:24Z

0

Use Array.prototype.flat for flatting the array, and then use a Set for distincting values and then create an array from the set using the Spread operator.

let arr = [{
    label: 'XYZ',
    colors: ['black', 'white', 'blue']
  },
  {
    label: 'PQR',
    colors: ['orange', 'yellow', 'white']
  },

  {
    label: 'ABC',
    colors: ['black', 'pink', 'blue']
  },
]

const vals = [...new Set(arr.map(i => i.colors).flat())]

console.log(vals)

edited May 2, 2020 at 11:31

answered May 2, 2020 at 11:28

Amir Popovich

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