javascript Cannot pass variables between 2 functions

Question

I am wondering how to pass a variable between 2 functions.

I have looked on Stackoverflow but all examples I tried did not work for me.

I have function, which calculates an array: arrR.

Now, I would like to call this variable somewhere else:

function my_function(arrR) {
    return(arrR[1]);
}

function onRefresh(chart) {
    chart.config.data.datasets.forEach(function(dataset) {
        dataset.data.push({
            x: Date.now(),
            y: myfunction(arrR)
        });
    });
}

But y: myfunction(arrR) gives notting. I have checked that if I put some number say y: 1 this works.

Any clue ?

Many thanks

What does `somewhere else` mean? Are you familiar with `scope` of function and variables? — Kostya Tresko, Jun 03 '20 at 08:12
See [What is the scope of variables in JavaScript?](https://stackoverflow.com/questions/500431/what-is-the-scope-of-variables-in-javascript) — Guy Incognito, Jun 03 '20 at 08:15

score 0 · Accepted Answer · edited Jun 03 '20 at 11:37

0

Can you get the value of the variable arrR?

If the scope of the variable arrR is different from onRefresh one level or higher. You can't get arrR across domains. You need to understand the scope of JavaScript

edited Jun 03 '20 at 11:37

Bhargav Rao

50,140
28
121
140

answered Jun 03 '20 at 08:18

GreenKing19

51
3

Yes I think so as alert(arrR[1]); gives the correct value – Jun 03 '20 at 08:29
If the scope of the variable arrR is different from onRefresh one level or higher. You can't get arrR across domains. You need to understand the scope of JavaScript – GreenKing19 Jun 03 '20 at 08:42
Ok. I understand I need to understand the scope of JavaScript. I have declared now `var arrR = [];` but it still does not work. – Jun 03 '20 at 08:46

score 0 · Answer 2 · answered Jun 03 '20 at 08:23

0

Try this instead. Also check if arrR is exist or not by using console.log()

function onRefresh(chart) {
    chart.config.data.datasets.forEach(function(dataset) {
        arrR.length > 0 && dataset.data.push({
            x: Date.now(),
            y: myfunction(arrR)
        });
    });
}

answered Jun 03 '20 at 08:23

rajan magar

11
2

Thanks. Tried but did not help. Where should I use console.log() ? Sorry I am really a noob – Jun 03 '20 at 08:30
before this line > chart.config.data.datasets.forEach – rajan magar Jun 03 '20 at 21:57

score 0 · Answer 3 · answered Jun 03 '20 at 08:30

0

your arrR variable is inside a function. It might be that the scope of that variable will be inside the function only.Try declaring this variable outside the function to use it globally.Hope it helps.:)

answered Jun 03 '20 at 08:30

Shivam Akhouri

1
1

score 0 · Answer 4 · 2020-06-03T13:02:21.350

0

Thanks everyone. This works now like: I just had to declare the variable outside functions.


var arrR = [];

edited Jun 03 '20 at 13:02

answered Jun 03 '20 at 08:48

javascript Cannot pass variables between 2 functions

4 Answers4