Append row based on value in another cell - arrays

Question

Using a Google App Script I'm looking to find any ID's from Sheet2 which exist in Sheet1 and append the comment field within Sheet1 with what is listed in the Comment field in Sheet2.
Sheet1: Holds all data based on ID
Sheet2: Holds comments relating to some ID's in Sheet1
Sheet1 Example
ID Type In Stock Comment
1 Apple Yes
2 Banana No
3 Orange Yes
Sheet2 Example
ID Comment
1 Text
2 Text
Code
This is code I've been using for something else which loops through my source data to identify a variable called "Yes", obviously this won't work for this case as the ID is the variable we need to find which is dynamic.
I'm just a bit lost on how to modify this code so that it will loop through Sheet2, get all the IDs, check those IDs against Sheet1. If those IDs exist in Sheet1 update the comment of Sheet1 with the comment already listed in Sheet2
function setComment(){
var outputSheet = SpreadsheetApp.getActiveSpreadsheet().getSheetByName("Sheet1");
var lastRow = outputSheet.getLastRow();
var lastCol = outputSheet.getLastColumn();
var targetValues = [];
var sourceSheet = SpreadsheetApp.getActiveSpreadsheet().getSheetByName("Sheet2");
var lastSourceRow = sourceSheet.getLastRow();
var lastSourceCol = sourceSheet.getLastColumn();
var sourceRange = sourceSheet.getRange(1, 1, lastSourceRow, lastSourceCol);
var sourceData = sourceRange.getValues();
{
//Loop through every retrieved row from the Source
for (row in sourceData) {
//IF Column I in this row has 'Yes', then work on it.
if (sourceData[row][1] === 'Yes') {
//Save it ta a temporary variable
var tempvalue = [sourceData[row][0], sourceData[row][7]];
//then push that into the variables which holds all the new values to be returned
targetValues.push(tempvalue);
}
}
//Save the new range to the appropriate sheet starting at the last empty row
outputSheet.getRange(lastRow + 1, 1 , targetValues.length, 2).setValues(targetValues);
}
}

Answer 1

Yes you need to loop through one group of IDs. In that loop you need to nest a loop that goes through the other group of IDs.
Code
function setComments() {
var ss = SpreadsheetApp.getActive(),
compare1 = "", compare2 = "",
outputSheet = ss.getSheetByName("Sheet1"),
sourceSheet = ss.getSheetByName("Sheet2"),
range1 = outputSheet.getDataRange(),
range2 = sourceSheet.getDataRange(),
lastCol1 = range1.getNumColumns(),
lastCol2 = range2.getNumColumns(),
values1 = range1.getValues(),
values2 = range2.getValues(),
// get the range of the titles
titleSection1 = outputSheet.getRange(1,1,1, lastCol1),
titleSection2 = sourceSheet.getRange(1,1,1, lastCol2),
// get the values from the titles
titles1 = titleSection1.getValues(),
titles2 = titleSection2.getValues(),
// get the column # for "ID" and "comment"
idCol1 = titles1[0].indexOf("ID"),
idCol2 = titles2[0].indexOf("ID"),
commentsCol1 = titles1[0].indexOf("comment"),
commentsCol2 = titles2[0].indexOf("comment");
// get the IDs from range1
for (i = 1; i < values1.length; i++) {
compare1 = values1[i][idCol1];
// get the IDs from range2
for (j = 1; j< values2.length; j++){
compare2 = values2[j][idCol2];
// if same ID, change the values array
if (compare1 == compare2) {
values1[i][commentsCol1] = values2[j][commentsCol2];
}
}
}
// set values based on the values array
range1.setValues(values1);
}