Array flattening

💡 It is a process through which we can reduce the dimension of the array

• We can use concat() method for flattening the array

let arr = [[1,2],[3,[4,9]],[5,6]];

let flattened= [].concat(...arr);
console.log(flattened); //[ 1, 2, 3, [ 4, 9 ], 5, 6 ]

• Use array.flat() method, here you have to give the depth level of the array

  for example: array.flat(2)
  

  let arr = [[1,2],[3,[4,9]],[5,6]];
  
  console.log(arr.flat(2)); //[ 1, 2, 3,  4, 9 , 5, 6 ]
  

• We can also make our own custom flat function for an array with the help of recursion
  

let arr = [[1,2],[3,[4,9]],[5,6]];

function customFlat(arr, dept = 1){
    let result = [];
    arr.forEach((ar) => {
        if(Array.isArray(ar) && dept>0){
            result.push(...customFlat(ar, dept-1))
        } else result.push(ar)
    });
    return result;
}

console.log(customFlat(arr, 2));

Comments

[Anthony Fung]

Cool tip!

Sometimes I have arrays of objects, where each object has a property that's also an array. In that scenario, I usually use flatMap

[Aditya Singh]

Yes, we can also use that for the same