Update custom function in different cells - google-apps-script

Question

I have a spreadsheet with a custom function calling a web API like this:
function myFunction(value) {
var value = value
...
}
and I call this function in different cells in B column in this way:
=myFunction(A2)
=myFunction(A3)
=myFunction(A4)
...
so that the values change regarding the content of A column.
Now, I would like to update all these functions with a trigger, which could be every minute, or every hour, or at midnight. I used the built in trigger on Google Apps Script interface, like I did in the past with external scripts, but it doesn't work (I think because the trigger call the function without the "value" variable).
I was thinking to add an external triggered script that update the value of another cell (let's suppose "C1"), and then use the onEdit function to update the custom functions. I searched a lot about onEdit, but I really didn't understand how to make it works in my case.
Should the onEdit function recall myFunction? In what way?
Any help is appreciated, thank you

Answer 1

You can use this function for refreshing formulas in your column:
function updateColumnBFormulas()
{
var ss = SpreadsheetApp.getActiveSpreadsheet();
var sheet = ss.getSheetByName('test');
var range = sheet.getRange(1, 2, sheet.getLastRow(), 1);
// get all formulas
var formulas = range.getFormulas();
for (var i = 0; i < formulas.length; i++)
{
// if there's formula in a cell
if (formulas[i][0])
{
// refresh it
sheet.getRange(i+1, 2).setFormula(formulas[i][0]);
}
}
}
Then set up trigger to run it every minute (Edit - Current project's trigger):

Answer 2

Ok, I solved with an external script that updates a cell, and then a dummy argument in my custon function that refers to that cell (as suggested by #RobinGertenbach)
This is the external triggered script:
function update() {
var number = Math.floor(new Date().getTime()/1000);
ss.getSheetByName("Data").getRange("A1").setValue(number);
}
and my custom function now looks like:
function myFunction(value, now) {
var value = value
var now = now
...
}
and then it is called in column B in this way:
=myFunction(A2, $A$1)
=myFunction(A3, $A$1)
=myFunction(A4, $A$1)
...
The solution with a function for refreshing formulas posted above was not doing the job, I don't know why. Formulas were refreshing but the values didn't get updated.
Thank you very much for your help!