Rewrite array from the function. Using argument reference

Question

Can you please explain how to worship JavaScript gods and work around this one.

var array = ['old'];
 
function manageArray(targetArray) {
 targetArray = ['new'];
}
manageArray(array);
alert(array);

The reason for this is to create a pattern that will have filter logic and instead of declaring explicit methods for each array have one universal to rule over all.

Desired logic

var numbers = ['1', '2']
var words = ['room', 'car']
var color = ['red', 'blue']
function manageArray(targetArray, value) {
 targetArray = targetArray.filter(existingValue, () => {
 return existingValue != value
 })
}
manageArray(words, 'car');
alert(words);

• StudioTime: What are you expecting to happen here? targetArray is scoped to your function

Answer 1

From what I understand, you want to pass your variable by reference. It is sad that Javascript pass array as value. There are a few ugly workaround.

var array = {v: ['old'] };
function manageArray(targetArray) {
 targetArray.v = ['new'];
}
manageArray(array);

or

var array = ['old'];
function manageArray(targetArray) {
 return ['new'];
}
array = manageArray(array);

For further reading:

• Pass Variables by Reference in Javascript

Answer 2

You'll be able to access the array if you have your function return it:

var array = ['old'];
 
function manageArray(targetArray) {
 targetArray = ['new'];
 return targetArray
}
array = manageArray(array);
alert(array);