App variable to be used in an equation

[Peter]

It would be nice if I could use a global variable in an equation in the data builder.

Use case:
We calculate for our sales price with a fixed exchange rate.
My solution would have been: make a table with one record only: the exchange rate.
Make a app variable from this record (this works already).
Alas in an equation I can not use this app variable.

Chem told me there is a workaround, but it would be great if you have global variables.

This is not the same, but also in the same direction: Page Variable suggestion

[brettlewis]

I’m interested in this too.

Chem did send me a suggestion around using JavaScript and the user logged in variables, but it was a bit too geeky for me. It made total sense the way he explained it, but it had a lot of moving parts and I was concerned about my ability to support / extend that solution.

[SWalker]

Has something like this ever come to fruition? This functionality would be very useful!

[moe]

This is likely not going to even be possible since all our equations are server side at the database level.

However, is this a value that’s only being used in view only? In that case, you might be able to achieve this with a dynamic field.

I’ll test this idea and report back.

[moe]

Yes, you can achieve this using a combination of local storage and a custom Handlebars helper. Here’s how:

Steps

1. Store the exchange rate in local storage:

localStorage.setItem('exchange_rate', '0.8790'); // Example rate

2. Create a custom Handlebars helper:

Handlebars.registerHelper('multiplyByExchangeRate', function (value) {
  const rate = parseFloat(localStorage.getItem('exchange_rate')) || 0;
  return value * rate;
});

3. Use the helper in your dynamic field:

{{multiplyByExchangeRate field_73}}

Be sure to wrap the Handlebars helper in event listener:

document.addEventListener('DOMContentLoaded', function () {
    
    Handlebars.registerHelper('multiplyByExchangeRate', function (value) {
            const rate = parseFloat(localStorage.getItem('exchange_rate')) || 0;
            return value * rate;
        });
    
  });

Here’s some screenshots of my configuration:

Important Notes

• This approach works only on the client-side (within the app interface).
• It won’t apply to server-side processes like exports or backend calculations.
• ChatGPT is amazing at writing the most powerful Handlebar Helpers.

Let me know if you need further clarification or assistance!