Combine an array of arrays with its elements reversed within the same array

Question

Combine an array of arrays with its elements reversed within the same array

I am working with an array of numbers that is structured like this:

const arrayOfArrays: number[][] = [[1, 2], [1, 3]];

The desired outcome is to have [[1, 2], [2, 1], [1, 3], [3, 1]].

I found a solution using the following approach:

// initialize an empty array
let result: number[][] = [];

for (const elArr of arrayOfArrays) {
    result.push(elArr);
    result.push(elArr.reverse());
}

However, I believe there might be more elegant ways to achieve this. Any suggestions?

javascript typescript

Answer 1

Answer №1

To achieve this, you can utilize the Array#flatMap method to obtain the desired outcome within a single iteration.

var matrix = [[1, 2], [1, 3]],
    output = matrix.flatMap(([...data]) => [[...data], data.reverse()]);

console.log(output);

Answer 2

To achieve this, you can utilize the Array#flatMap method to obtain the desired outcome within a single iteration.

var matrix = [[1, 2], [1, 3]],
    output = matrix.flatMap(([...data]) => [[...data], data.reverse()]);

console.log(output);

Answer 3

Answer №2

Although your solution is clever, I decided to try a different approach:

let array = [[1, 2], [1, 3]];

let transformedArray = array.map((value, index) => {
    return [value, array[index].slice().reverse()];
}).flat();

Keep in mind that Array.flat() is a new feature, so feel free to refer to the ES specification here

Answer 4

Although your solution is clever, I decided to try a different approach:

let array = [[1, 2], [1, 3]];

let transformedArray = array.map((value, index) => {
    return [value, array[index].slice().reverse()];
}).flat();

Keep in mind that Array.flat() is a new feature, so feel free to refer to the ES specification here

Combine an array of arrays with its elements reversed within the same array

Answer №1

Answer №2

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