Agfdhyk

can you explain the logic how to convert this 2d array to array and in array has objects, here is the input :

const arr = [

["Tony", "a", "b"],

["Sara", "c", "z"]

           ];

how to convert them to be:

obj = [

{

 name:"Tony", 

 first:"a", 

 second:"b"

},

{

 name:"Sara", 

 first:"c", 

 second:"z"

}

   ]

should we create 2 objects temporary and are ? to put them in the array,
and how about looping? can we just use one-time looping?
and how if that 2d array length is not same with ther 2d on the first or the second,

i do love to know the method, with explaning if you dont mind,
and i do like you all dont use ES6 for this :), so i know the logic

Use Array.map(). In the map's callback, extract the values to variables, using array destructuring, than create the object with shorthand property names:

const arr = [["Tony", "a", "b"], ["Sara", "c", "z"]];



const result = arr.map(([name, first, second]) => ({

  name,

  first,

  second

}));



console.log(result);

And if you don't want to use Array.map(), you can build one using a for...of loop:

const map = (arr, cb) => {

  const r = ;

  

  for(const item of arr) {

    r.push(cb(item));

  }

  

  return r;

};



const arr = [["Tony", "a", "b"], ["Sara", "c", "z"]];



const result = map(arr, ([name, first, second]) => ({

  name,

  first,

  second

}));



console.log(result);

You can use .map() with some array destructuring:

const arr = [

  ["Tony", "a", "b"],

  ["Sara", "c", "z"]

];



const result = arr.map(([name, first, second]) => ({name, first, second}));



console.log(result);

.as-console-wrapper { max-height: 100% !important; top: 0; }

Alternatively, you can use a simple for loop:

const arr = [

  ["Tony", "a", "b"],

  ["Sara", "c", "z"]

];



const result = ;



for(var i = 0; i < arr.length; i++) {

  result.push({

    name: arr[i][0],

    first: arr[i][1],

    second: arr[i][2]

  });

}



console.log(result);

.as-console-wrapper { max-height: 100% !important; top: 0; }

var arr = [["Tony", "a", "b"], ["Sara", "c", "z"]];



function parseData(input){ 

    var output = ;

    for(var i = 0; i< input.length ; i++){

        output.push({name:input[i][0],first:input[i][1],second:input[i][2]})

    }

    return output;

}

console.log(parseData(arr));

EDIT - Explanation

As the input is structured as 2D array with inner array is of fixed length of 3 and outer is of non-negative ( >= 0 ). Iterate over the outer array using for loop and inner array using the index number and store the result in output array.

JsFiddle demo - https://jsfiddle.net/53umf8rv/

Without Map:

const arr = [

["Tony", "a", "b"],

["Sara", "c", "z"]

           ];



obj=; 

for(innerArr of arr)

{

obj.push({"name":innerArr[0],"first":innerArr[1],"second":innerArr[2]});

}



console.log(obj);

Without using higher order functions you can achieve this using a for of loop:

const arr = [

  ["Tony", "a", "b"],

  ["Sara", "c", "z"]

];



let obj_arr = ;



for(inner_arr of arr) {

  obj_arr = [...obj_arr, {name: inner_arr[0], first: inner_arr[1], second: inner_arr[2]}];

}



console.log(obj_arr);