How can I group an array with nested array?

Does anyone know a simple way to group an array with nested array? For example, i have an array of animals:

[
  ['Cat', 'Dog', 'Monkey'],
  ['my pet', 'it is animals', 'terrestrial animals']
]

I want to make new array with format that's grouped by ['Cat', 'Dog', 'Monkey']:

[
  {
    groupTitle: 'Cat',
    relations: ['my pet', 'it is animals', 'terrestrial animals']
  },
  {
    groupTitle: 'Dog',
    relations: ['my pet', 'it is animals', 'terrestrial animals']
  },
  {
    groupTitle: 'Monkey',
    relations: ['my pet', 'it is animals', 'terrestrial animals']
  }
]

How can i do it? Thanks!

Solution 1:

Using map()

const arr = [
  ['Cat', 'Dog', 'Monkey'],
  ['my pet', 'it is animals', 'terrestrial animals']
]; // original data
const [groupTitles, relations] = arr; // array destructuring to get individual sub-arrays

const result = groupTitles.map(groupTitle => ({
  groupTitle,
  relations
}));

console.log(result); // print result

I used the following approach to achieve your desired outcome.

1. Use Array destructuring to get the individual arrays from the original array.
2. map() through the animals array to get the desired array of objects and store it in a result variable.

Using reduce()

const arr = [
  ['Cat', 'Dog', 'Monkey'],
  ['my pet', 'it is animals', 'terrestrial animals'],
]; // original array

const result = arr[0].reduce((a, b) => {
  return [
    ...a, // previously calculated values
    { // new value
      groupTitle: b,
      relations: arr[1],
    },
  ];
}, []);

console.log(result); // print result

The same result can also be achieved using reduce() method as required.

Solution 2:

You can make a nested iteration using for loop for example:

const arr = [
  ["Cat", "Dog", "Monkey"],
  ["my pet", "it is animals", "terrestrial animals"],
];

let newArr = [];

for (let i = 0; i <= arr.length; i++) {
  for (let j = 0; j < arr[0].length; j++) {}
  newArr.push({ groupTitle: arr[0][i], relations: arr[1] });
}

console.log(newArr);

Solution 3:

Using destructuring assignments

const arr = [
  ['Cat', 'Dog', 'Monkey'],
  ['my pet', 'it is animals', 'terrestrial animals']
]

let a,b,c, obj, newArr = [];

[a,b,c] =  arr[1]

arr[0].forEach(el => {

  obj = {
    groupTitle: el,
    relations: [a,b,c]
  }
  newArr.push(obj)
})

console.log(newArr)