Google Sheets Script: Passing function as a parameter

Question

I've made a script in Google Sheets:

/**
 * @param {array} input A row or a column.
 * @param {function} condition A function returning bool.
 * @return The last value in the input satisfying the condition.
 * @customfunction
 */
function GetLastGoodValIn1DArray(input, condition) {
  // realization ...
}

When I'm trying to call this function with the next arguments:

=GetLastGoodValIn1DArray(D11:H11;ISNUMBER)

I'm getting the next error:

Error

TypeError: #NAME? is not a function, but a string. (line 26).

Obviously 'ISNUMBER' interpreted as a string. But how to pass it as a function?

Answer 1

It's not is possible to access internal google sheets functions from a script according to this old google docs forum and this Stack Overflow question .

Note that even google sheets internal functions can't take functions as parameters. For example, the internal function SUBTOTAL , instead of taking the function directly, takes in a numerical code that corresponds to the desired function.

The best I can think of is to build your own WorksheetFunction object like excel has for vba. That could be an object map that takes in an string and returns a function you wrote. For example:

var worksheetFunction = {
  isnumber: function (x) {
    return !isNaN(x);
  }
};

Another Note : ISNUMBER isn't passed as a string to your custom function. Google sheets first calculates it as an error and then passes the string #NAME? to your custom function. You can see this by using the formula =type(ISNUMBER) , which returns 16 (the code for an error) also in your custom function condition === "#NAME?" will evaluate to true.