How to change a variable that was called in parameters JavaScript

Question

Im working on a project, and in an attempt to shorten the amount of code I wrote a function to call all of them at once. It looks something like this function Function(peram1) {peram1 = peram1 += 5}; And I call it like so Function(someVariable) My issue is that I need to change the variable someVariable from inside the function, even though the value of peram1 is simply just the value of someVariable, but cant directly change it. I call multiple of these functions, so I cant simply just call the actual variable name from within.

var someVariable = 5;
var someSeperateVariable = 8;

function Function(peram1) {
    peram1 = peram1 += 5;
};

Function(someVariable);
Function(someSeperateVariable);
console.log(someVariable, someSeperateVariable);

what is the type of your `someVariable`? object, number, string, array? — Pranesh Ravi, Sep 26 '16 at 18:26
Are you able to show an example, I don't really understand the question. — putvande, Sep 26 '16 at 18:27
The long and short of it is that Javascript does not have references like PHP or C++. — Jhecht, Sep 26 '16 at 18:31
@putvande Added one, hope it explains it a little bit better. — TheChosenWhanMC, Sep 26 '16 at 18:32
@vlaz is there any way I could directly access the variable without writing 7 seperate functions for each variable I need changed? — TheChosenWhanMC, Sep 26 '16 at 18:33
Directly? No. Objects you can modify from inside functions, though. However, I believe you are approaching this incorrectly - I am almost certain that you want to just return the value instead, as that is completely idiomatic JavaScript. Passing a variable, and modifying the original is idiomatic C code. — VLAZ, Sep 26 '16 at 18:36

chenop · Answer 1 · 2016-09-26T18:58:42.507

0

Consider returning a value from Function

var peram1 = Function(Peram1);

Another option in case peram1 is not an object - is to wrap peram1 with an object:

var objContainPeram1 = {    peram1: peram1 }

Function (objContainPeram1) {
     objContainPeram1.peram1 = objContainPeram1.peram1 + 5  
}

edited Sep 26 '16 at 18:58

answered Sep 26 '16 at 18:33

chenop

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Would that require me to make an object containing the variables? – TheChosenWhanMC Sep 26 '16 at 18:35
Yes, See my edit. – chenop Sep 26 '16 at 18:36

score 0 · Accepted Answer · answered Sep 26 '16 at 18:43

You can use an object to store variables, pass property name and object to function

var obj = {someVariable:5, someSeparateVariable:8};

function fn(prop, obj) {
    obj[prop] += 5;
};

fn("someVariable", obj);
fn("someSeparateVariable", obj);
console.log(obj.someVariable, obj.someSeparateVariable);

score 0 · Answer 3 · answered Sep 26 '16 at 19:08

Another solution would be to wrap your code in a function to create a closure:

function closure() {

    var someVariable = 5;
    var someSeperateVariable = 8;

    function foo() {
        someVariable += 5;
    };

    console.log(someVariable)
    foo()
    console.log(someVariable)

}

closure()

How to change a variable that was called in parameters JavaScript

3 Answers3