google sheets - Using built-in spreadsheet functions in a script

Question

I'm using Google App Script for the first time. I'm using it on a Google Doc spreadsheet.

I'm trying very simple functions, just to learn the basics. For example this works:

function test_hello() {
    return 'hello';
}

But I'm puzzled by this simple one :

function test_today() {
    return today();
}

It makes an #ERROR! wherever I use it. And when I put my cursor on it, it says :

error : ReferenceError: "today" is not defined.

While the today() function works when used directly in the spreadsheet.

Does this mean that in scripts, I cannot use spreadsheet built-in functions? Is there any elegant way around this?

Some spreadsheet functions are quite useful to me (I like weekday() for example).

A non-elegant way could be to create columns to calculate intermediate values that I need, and that can be calculated with spreadsheet functions. But I'd rather avoid something this dirty and cumbersome.

Answer 1

Google Apps Script is a subset of JavaScript, spreadsheet functions are currently not supported. For example, if you want to create a function that returns today's date you should write :

function test_today(){
return new Date()
}// note that this will  eventually return a value in milliseconds , you'll have to set the cell format to 'date' or 'time' or both ;-)

syntax is the same as with sheet functions : =test_today() see tutorial

There are many internet ressources on javascript, one of the most useful I found is w3school