Detect formula errors in Google Sheets using Script - google-apps-script

Question

My ultimate goal is here, but because I've gotten no replies, I'm starting to learn things from scratch (probably for the best anyway). Basically, I want a script that will identify errors and fix them
Well, the first part of that is being able to ID the errors. Is there a way using Google Script to identify if a cell has an error in it, and return a particular message as a result? Or do I just have to do an if/else that says "if the cell value is '#N/A', do this", plus "if the cell value is '#ERROR', do this", continuing for various errors?. Basically I want ISERROR(), but in the script

Answer 1

Use a helper function to abstract away the nastiness:
function isError_(cell) {
// Cell is a value, e.g. came from `range.getValue()` or is an element of an array from `range.getValues()`
const errorValues = ["#N/A", "#REF", .... ];
for (var i = 0; i < errorValues.length; ++i)
if (cell == errorValues[i])
return true;
return false;
}
function foo() {
const vals = SpreadsheetApp.getActive().getSheets()[0].getDataRange().getValues();
for (var row = 0; row < vals.length; ++row) {
for (var col = 0; col < vals[0].length; ++col) {
if (isError_(vals[row][col])) {
Logger.log("Array element (" + row + ", " + col + ") is an error value.");
}
}
}
}
Using Array#indexOf in the helper function:
function isError_(cell) {
// Cell is a value, e.g. came from `range.getValue()` or is an element of an array from `range.getValues()`
// Note: indexOf uses strict equality when comparing cell to elements of errorValues, so make sure everything's a primitive...
const errorValues = ["#N/A", "#REF", .... ];
return (errorValues.indexOf(cell) !== -1);
}
If/when Google Apps Script is upgraded with Array#includes, that would be a better option than Array#indexOf:
function isError_(cell) {
// cell is a value, e.g. came from `range.getValue()` or is an element of an array from `range.getValues()`
const errorValues = ["#N/A", "#REF", .... ];
return errorValues.includes(cell);
}
Now that the v8 runtime is available, there are a number of other changes one could make to the above code snippets (arrow functions, etc) but note that changing things in this manner is not required.

Answer 2

Update: 25 March 2020
#tehhowch remarked "If/when Google Apps Script is upgraded with Array#includes, that would be a better option than Array#indexOf".
Array.includes does now run in Apps Script and, as anticipated provides a far more simple approach when compared to indexOf.
This example varies from the previous answers by using a specific range to show that looping through each cell is not required. In fact, this answer will apply to any range length.
The two key aspects of the answer are:
map: to create an array for each column
includes: used in an IF statement to test for a true or false value.
function foo() {
var ss = SpreadsheetApp.getActiveSpreadsheet();
var sourcename = "source_sheet";
var source = ss.getSheetByName(sourcename);
var sourcerange = source.getRange("A2:E500");
var sourcevalues = sourcerange.getValues();
// define the error values
var errorValues = ["#NULL!", "#DIV/0!", "#VALUE!", "#REF!", "#NAME?", "#NUM!", "#N/A","#ERROR!"];
// loop though the columns
for (var c = 0;c<5;c++){
// create an array for the column
var columnoutput = sourcevalues.map(function(e){return e[c];});
// loop through errors
for (var errorNum=0; errorNum<errorValues.length;errorNum++){
// get the error
var errorvalue = errorValues[errorNum]
// Logger.log("DEBUG: column#:"+c+", error#:"+e+", error value = "+errorvalue+", does col include error = "+columnoutput.includes(errorvalue));
// if the error exists in this column then resposnse = true, if the error doesn't exist then response = false
if (columnoutput.includes(errorvalue) != true){
Logger.log("DEBUG: Column#:"+c+", error#:"+errorNum+"-"+errorvalue+" - No ERROR");
} else {
Logger.log("DEBUG: column#:"+c+", error#:"+errorNum+"-"+errorvalue+"- ERROR EXISTS");
}
}
}
return;
}

Answer 3

Shorter yet, use a nested forEach() on the [vals] array, then check to see if the cell value matches a value of the [errorValues] array with indexOf. This was faster than a for loop...
function foo() {
const errorValues = ["#NULL!", "#DIV/0!", "#VALUE!", "#REF!", "#NAME?", "#NUM!", "#N/A","#ERROR!"];
const vals = SpreadsheetApp.getActive().getSheets()[0].getDataRange().getValues();
vals.forEach((val,row) => { val.forEach((item, col) => {
(errorValues.indexOf(item) !== -1) ? Logger.log("Array element (" + row + ", " + col + ") is an error value.") : false ;
});
});
}

Answer 4

I had a similar question and resolved using getDisplayValue() instead of getValue()
Try something like:
function checkCells(inputRange) {
var inputRangeCells = SpreadsheetApp.getActiveSheet().getRange(inputRange);
var cellValue;
for(var i=0; i < inputRangeCells.length; i++) {
cellValue = inputRangeCells[i].getDisplayValue();
if (cellValue=error1.....) { ... }
}
}
Display value should give you what's displayed to the user rather than #ERROR!