How to deal with duplicates in google sheets script? - google-apps-script

Question

So in the project I want to do I have a google sheet with timestamps and names next to those timestamps in the spreadsheet. I am having trouble accounting for duplicates and giving the name multiple timestamps in another google sheet.
for(var i = 0; i < length; i++){//for loop 1
if(currentCell.isBlank()){//current cell is blank
daySheet.getRange(i+10, 2).setValue(fullName);//set name to first cell
daySheet.getRange(i+10,3).setValue(pI);
daySheet.getRange(i+10,day+3).setValue(1);
}else if(counter > 1 ){//the index of the duplicate in the sheet month
//if counter is > 1 then write duplicates
for(var t = 1; t <= sheetLength ; t++){//loop through sign in sheet
//current index i
if(signInLN == signInSheet.getRange(t+1,3).getValue()){
//if there is a match
daySheet.getRange(t+10,day+3).setValue(1);
//day is equal to the day I spliced from the timestamp
//at this point I am confused on how to get the second date that has the same
//name and add to the row with the original name.
//when i splice the timestamp based on the row of index i, with duplicates I get
//the day number from the first instance where the name is read
}
}
}//for loop 1
How can I get this to work with duplicates so I can account for the dates but make sure that if there are
any duplicates they will be added to the row of the original name
Google Sheet EX:
12/10/2020 test1
12/11/202 test2
12/15/2020 test1
Should be something like this:
name 10 11 12 13 14 15 16
test1 1 1
test2 1
//the one is to identify that the date is when the user signed in on the sheets.

Answer 1

Sample Spreadsheet:
Code snippet done with Apps Script, adapt it to your needs.
use Logger.log() in case you don't understand parts of code
It is done mainly with functional JavaScript
function main(){
var inputRange = "A2:B";
var sheet = SpreadsheetApp.getActive().getSheets()[0]
var input = sheet.getRange(inputRange).getValues(); //Read data into array
var minDate, maxDate;
var presentDates = input.map(function(row) {return row[0];}); //Turns input into an array of only the element 0 (the date)
minDate = presentDates.reduce(function(a,b) { return a<b?a:b}); //For each value, if its the smallest: keep; otherwise: skip;
maxDate = presentDates.reduce(function(a,b) { return a>b?a:b}); //Same as above, but largest.
var dates = [];
for (var currentDate = minDate; currentDate <= maxDate; currentDate.setDate(currentDate.getDate()+1)) {
dates.push(getFormattedDate(currentDate)); //Insert each unique date from minDate to maxDate (to leave no gaps)
}
var uniqueNames = input.map(function(row) {return row[1];}) //Turns input into an array of only the element at 1 (the names)
.filter(function (value, index, self) {return self.indexOf(value) === index;}); //Removes duplicates from the array (Remove the element if the first appearence of it on the array is not the current element's index)
var output = {}; //Temporary dictionary for easier counting later on.
for (var i=0; i< dates.length; i++) {
var dateKey = dates[i];
for (var userIndex = 0; userIndex <= uniqueNames.length; userIndex++) {
var mapKey = uniqueNames[userIndex]+dateKey; //Match each name with each date
input.map(function(row) {return row[1]+getFormattedDate(row[0])}) //Translate input into name + date (for easier filtering)
.filter(function (row) {return row === mapKey}) //Grab all instances where the same date as dateKey is present for the current name
.forEach(function(row){output[mapKey] = (output[mapKey]||0) + 1;}); //Count them.
}
}
var toInsert = []; //Array that will be outputted into sheets
var firstLine = ['names X Dates'].concat(dates); //Initialize with header (first element is hard-coded)
toInsert.push(firstLine); //Insert header line into output.
uniqueNames.forEach(function(name) {
var newLine = [name];
for (var i=0; i< dates.length; i++) { //For each name + date combination, insert the value from the output dictionary.
var currentDate = dates[i];
newLine.push(output[name+currentDate]||0);
}
toInsert.push(newLine); //Insert into the output.
});
sheet.getRange(1, 5, toInsert.length, toInsert[0].length).setValues(toInsert); //Write the output to the sheet
}
// Returns a date in the format MM/dd/YYYY
function getFormattedDate(date) {
var year = date.getFullYear();
var month = (1 + date.getMonth()).toString();
month = month.length > 1 ? month : '0' + month;
var day = date.getDate().toString();
day = day.length > 1 ? day : '0' + day;
return month + '/' + day + '/' + year;
}
Run script results: