How to Zip Two Arrays in JavaScript

How do I zip two arrays in JavaScript?

Use the map method:

var a = [1, 2, 3]

var b = ['a', 'b', 'c']

var c = a.map(function(e, i) {

  return [e, b[i]];

});

console.log(c)

How to zip two arrays object in Javascript

Not sure if this is the most efficient way to do this, but it works for the example provided. This method relies on some relatively newer features of JavaScript, but ES6 is widely supported, so it hopefully won't be an issue in your case.

First, isolate the values in arr1 to be used as the object properties for the final result.

Then, re-map the objects of the second array by extracting the values from each object using Object.values() and reduce that to an object with the property names from the first array.

var arr1 = [{a: 'QQQ'}, {b: 'WWW'}];
var arr2 = [{a: 'EEE', b: 'RRR'}, {a: 'TTT', b: 'YYY'}];

var keys = arr1.reduce((valueArray,obj) => [...valueArray, ...Object.values(obj)],[]);

var results = arr2.map(o => Object.values(o).reduce((newObj,v,i) => ({...newObj,[keys[i]]:v}),{}),[])

console.log(results);

How to zip two arrays into one array which every array contains another array

You had the right basic idea. Issue you had is you were mixing up the indexes. And you were not returning anything in the map calls.

const productTitles = [
  ['a', 'aa'],
  ['b', 'bb'],
];

const productQuantity = [
  [1, 11],
  [2, 22],
];

const merged2 = productTitles.map((row, rowIndex) =>
  row.map((value, columnIndex) => [value, productQuantity[rowIndex][columnIndex]]));

console.log(merged2);

// Use flatMap if you do not want a nested array

const mergedFlat = productTitles.flatMap((row, rowIndex) =>
  row.map((value, columnIndex) => [value, productQuantity[rowIndex][columnIndex]]));

console.log(mergedFlat);

zip two arrays Javascript

Will a straightforward loop do it?

array3 = new Array();

for(var i = 0; i < array1.length; i++)
{
    array3.push(array1[i]);
    array3.push(array2[i]);
}

Merging (zipping) two arrays of different length with map() in JavaScript

.map will necessarily create a new array which is the same length as the array being iterated over. Because countries has 3 items, your output will also have 3 items (an array of arrays) if you use countries.map.

Using .map won't work here, because none of your input arrays are the same length as the desired output array. Either .push to an outside variable, like you already know about, or use .reduce and push to the accumulator:

const countries = ['US', 'FR', 'IT']

const area = [100, 105, 110, 115, 120, 125, 130]

const merged = countries.reduce((merged, c) => {

  area.forEach((a) => {

    merged.push(c + a);

  });

  return merged;

}, []);

console.log(merged);

Systematacally combining arrays

Do like:

const a = ['one', 'two', 'three'], b = ['a', 'b', 'c'], c = ['1', '2', '3'], combo = [];
for(let i=0,l=a.length; i<l; i++){
  combo.push([a[i], b[i], c[i]]);
}
console.log(combo);