Access every other item in an array - JavaScript

Question

Is it possible for me to access every other item in an array? So basically, all items in positions 0, 2, 4, 6 etc.

Here's my code if it helps:

function pushToHash(key, value) {
    for (var t = 0; t < value.length; t++) {
    MQHash[key[t]] = value.slice(0, lineLength[t]);
    }
}

So, I need to get every other value of lineLength. I only want this for lineLength, not key. I was thinking of doing a modulus, but wasn't sure how I'd implement it. Any ideas?

Thanks in advance!

Answer 1

Here is a function that will truncate an array every X elements (factor).

const truncateArray = (array: any[], factor: number): any[] => {
  let lastNumber = 0;
  return array.filter((element, index) => {
    const shouldIncludeThisElement = index === lastNumber + factor ? true : false;
    lastNumber = shouldIncludeThisElement ? index : lastNumber;
    return shouldIncludeThisElement;
  });
};

Answer 2

You can use the index (second parameter) in the array filter method like this:

let arr = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10];

// filter out all elements that are located at an even index in the array.

let x = arr.filter((element, index) => {
  return index % 2 === 0;
})

console.log(x) 
// [1, 3, 5, 7, 9]

Answer 3

If you just want this with lineLength and not with key, then add a second variable and use += when incrementing:

function pushToHash(key, value) {
    for (var t = 0, x = 0; t < value.length; t++, x += 2) {
        MQHash[key[t]] = value.slice(0, lineLength[x]);
    }
}

(The power of the comma operator...)