Linearize a BOM, issue when using setValues(result) instead of appendRow - google-apps-script

Question

Input is as follows (this is a simplified example)
LEVEL
NAME
JOB
1
A
Alpha
2
B
Bravo
3
C
Charlie
4
D
Delta
2
E
Echo
3
F
Foxtrot
2
G
Golf
2
H
Hotel
3
I
India
4
J
Juliet
I have to linearize to obtain that output
NAME level 1
JOB level 1
NAME level 2
JOB level 2
NAME level 3
JOB level 3
NAME level 4
JOB level 4
A
Alpha
B
Bravo
C
Charlie
D
Delta
A
Alpha
E
Echo
F
Foxtrot
A
Alpha
G
Golf
A
Alpha
H
Hotel
I
India
J
Juliet
I achive that by using a temporary array (temp) and appendRow, which is a bit slow. When I manage to use a big array (result) and setValues(result), I only get the last row
NAME level 1
JOB level 1
NAME level 2
JOB level 2
NAME level 3
JOB level 3
NAME level 4
JOB level 4
A
Alpha
H
Hotel
I
India
J
Juliet
A
Alpha
H
Hotel
I
India
J
Juliet
A
Alpha
H
Hotel
I
India
J
Juliet
A
Alpha
H
Hotel
I
India
J
Juliet
I can't understand what is wrong in my script ! Any help to understand will be usefull.
https://docs.google.com/spreadsheets/d/1zoT9kk-Am_yUOLCAAvccJOTH0UZ7lrRiLYpPtqb9RXY/copy
function linearize() {
const sh = SpreadsheetApp.getActiveSpreadsheet().getSheetByName('Original')
const data = sh.getRange(2, 1, sh.getLastRow() - 1, sh.getLastColumn()).getDisplayValues()
const nbData = sh.getLastColumn() - 1
const bd1 = SpreadsheetApp.getActiveSpreadsheet().getSheetByName('BD1') // for test with appendrow
const bd2 = SpreadsheetApp.getActiveSpreadsheet().getSheetByName('BD2') // for test with result
bd1.clearContents()
bd2.clearContents()
let result = []
let levelMax = 0
let headers = []
data.forEach(r => levelMax = Math.max(levelMax, r[0]))
for (let i = 1; i <= levelMax; i++) {
headers.push(['NAME level ' + i, 'JOB level ' + i])
}
bd1.appendRow(headers.flat())
result.push(headers.flat())
// everything ok until this step ==============
let temp = []
data.forEach(function (r, i) {
// save values
var level = r[0]
for (let x = 0; x < nbData; x++) {
temp[nbData * (level - 1) + x] = r[x + 1]
}
// blank values from level+1 to levelMax
if (level < levelMax) {
for (let y = (level * 1 + 1); y <= levelMax; y++) {
for (let x = 0; x < nbData; x++) {
temp[nbData * (y - 1) + x] = ''
}
}
}
// output when the following level will not increase or at the final row
if (i < data.length - 1) {
if (data[i + 1][0] <= data[i][0]) {
bd1.appendRow(temp)
result.push(temp)
}
}
else {
bd1.appendRow(temp)
result.push(temp)
}
})
bd2.getRange(1, 1, result.length, result[0].length).setValues(result)
}

Answer 1

I believe your goal is as follows.
By modifying your script, you want to achieve the situation of I have to linearize to obtain that output using bd2.getRange(1, 1, result.length, result[0].length).setValues(result).
In this case, how about the following modification?
From:
if (i < data.length - 1) {
if (data[i + 1][0] <= data[i][0]) {
bd1.appendRow(temp)
result.push(temp)
}
}
To:
if (i < data.length - 1) {
if (data[i + 1][0] <= data[i][0]) {
bd1.appendRow(temp);
result.push([...temp]); // <--- Modified. Or result.push(temp.slice())
}
}
I thought that in your script, temp is used as the pass-by-reference. By this, the issue of I only get the last row occurs. I thought that this might be the reason for your issue. So, in this case, temp is copied with [...temp] and/or temp.slice(). By this, it becomes the pass-by-value.