google-apps-script Create a custom function for Google Sheets Basic Example
Example
To avoid unsightly #DIV/0 errors in a spreadsheet, a custom function can be used.
/**
* Divides n by d unless d is zero, in which case, it returns
* the given symbol.
*
* @param {n} number The numerator
* @param {d} number The divisor
* @param {symbol} string The symbol to display if `d == 0`
* @return {number or string} The result of division or the given symbol
*
* @customfunction
*/
function zeroSafeDivide(n, d, symbol) {
if (d == 0)
return symbol;
else
return n / d;
}
To use the function, it needs to be bound to a spreadsheet using the script editor (Tools -> Script editor...). Once the function is added, it can be used like any other google sheets function by calling the function in a cell's formula.
Note how the function shows up in autocomplete when typed into a formula. This is due to the multi-line comment above the function declaration which is used to describe what the function does similar to JSDoc and Javadoc. To have the formula show up in autocomplete, the @customfunction tag must be specified in the comment.
