Multi tool use

How to run a function with optional argument/parameter in Google Apps Script

I am trying to run a function which has an optional argument/parameter in Google Apps Script. The function will create a Google Document and will also create a Google Slide if the user selects Yes. My problem is when the extractReplace function is being called, an error will occur because the copySlide is not defined.

Here's how I'm calling the function:

var copyId = DriveApp.getFileById(documentTemplate)
.makeCopy(documentName + folderName, nsdestinationFolder)
.getId();
var copyDocument = DocumentApp.openById(copyId);
var copyBody = copyDocument.getActiveSection();

//call function to create technical slide proposal
if(createTemplate == "Yes"){
createSlideProposal();
}
else{
extractReplace(copyBody, copySlide = 0);
}


I have tried copySlide = 0, false, null, but it did not work as the copySlide is not defined when is passes to the copySlide.replaceAllText line. There is another function which includes the copySlide variable but it will only be called and passed to the extractReplace function if the user select "Yes" to create the slide proposal (powerpoint).

copySlide

copySlide.replaceAllText

copySlide

extractReplace

Here's the function that uses copySlide

copySlide

function extractReplace(copyBody, copySlide) {
var result = ""; //result variable string = 0
var ss = SpreadsheetApp.openById("IDKEYHERE");
var firstDatabasesheet = ss.getSheets()[0];
var data = firstDatabasesheet.getDataRange().getValues();

data.forEach(function(row) {
if (row[32] == TMSreferenceNumber){
result = row[2] || row[16]; //chooses whichever cell that has something in it
copyBody.replaceText('repbranchOffice', result); //replaces text in document template
result = row[3] || row[17];
copyBody.replaceText('repsalesContact', result);
result = row[4] || row[18];
copyBody.replaceText('repbranchReferenceNumber', result);
result = row[5] || row[19];
copyBody.replaceText('rependUser', result);
copySlide.replaceAllText('rependUser', result); //for slide
}
...


2 Answers
2

Replace

extractReplace(copyBody, copySlide = 0);


with

extractReplace(copyBody, 0);


When working with optional arguments, you generally need to test for their absence if you do not provide a default value.

At the call site, you generally want to be able to omit parameters if they are optional and not important to you: foo(rq) vs. foo(rq, someParamIdontCareAbout) or foo(rq, 0), since it reduces the complexity of your call site code.

foo(rq)

foo(rq, someParamIdontCareAbout)

foo(rq, 0)

In the function with optional parameters, you want to initialize the values if they are needed (e.g. primitives, flags), or guard code blocks which interact with an optional class argument (like a reference to a Slide object).

Slide

Initialization:

function foo(required, startVal = /* something */) {
...
}
function foo(required, startVal) {
if (startVal === undefined) {
/* more than a one-statement initialization */
}
...
}


Block guards

function foo(required, objectRef) {
/* Code that does not need the object reference */
if (objectRef) {
/*
* Code that needs the object reference
* objectRef.someMethod(...);
*/
}
/* More code that does not need the object reference */
}


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