My input is const :

input = [
  ["A", "B", "C", "D"],
  ["a", "b", "c"],
  [1, 2, 3, 4, 5, 6]
 ];

// Expected output

const output = ["A", "a", 1, "B", "b", 2, "C", "c", 3, "D", 4, 5, 6];

So I write a JavaScript code to achieve output,

Array.prototype.insert = function ( index, item ) {
    this.splice( index, 0, item );
};
let lengthInputArray = input.length;
let outputArray = [];
let lengthArray = [];
for(let indexInput = 0; indexInput < input.length; indexInput  ){
  lengthArray.push(input[indexInput].length);
}
let maxLen = Math.max(...lengthArray);

for(let maxIndex = 0; maxIndex < maxLen; maxIndex  ){
  for (var indexArr of input) {
    if(indexArr.length <= maxLen){
      var tobeInsertValue = indexArr[maxIndex];
      if(tobeInsertValue != undefined){
        outputArray.push(tobeInsertValue);
      }
    }
  }
}
console.log("outputArray : "   outputArray);

Can anybody suggest me about good solution or optimum way to solve the problem ?

CodePudding user response：

You could also try transposing the array based on the longest array index then use flat and filter to bring out the flatten form without any undefined elements (undefined due to the unequal length of array elements)

let input = [
  ["A", "B", "C", "D"],
  ["a", "b", "c"],
  [1, 2, 3, 4, 5, 6]
];
  
let arrayLen = input.map(x => x.length);
let maxLen = Math.max(...arrayLen)
let maxIndex = arrayLen.indexOf(maxLen)
console.log(input[maxIndex].map((_, colIndex) => input.map(row => row[colIndex])).flat().filter(x => x));

CodePudding user response：

Just a simple nested loop can work, as long as you appropriately handle the ending length:

const input = [
  ["A", "B", "C", "D"],
  ["a", "b", "c"],
  [1, 2, 3, 4, 5, 6]
];

const maxLen = Math.max(...input.map(({ length }) => length));

let out = [];

for (let i = 0; i < maxLen; i  ) {
  for (let j = 0; j < input.length; j  ) {
    if (input[j].length > i) {
      out.push(input[j][i]);
    }
  }
}

console.log(out);

.as-console-wrapper { max-height: 100% !important; top: auto; }

I looped through each of the sub-arrays in order, and add the values at the correct position to the output array in their correct order.