App Script in Google Sheets - problem with data auto complete

I have two sheets. In one, the data of the manufactured devices is already entered. In the second, new warranty claims are added daily. To shorten the working time, I automatically copy the production data from the sheet Production to sheet Complaints. Currently I am solving this with VLOOKUP or INDEX function. But it works very slow when number of rows >20k.

Is it possible to write a script (using AppScripts) where after entering the ID number in the complaint sheet and selecting this cell, script will independently fill in the appropriate columns with data from 'Production'? (the order of the columns is different in both sheet)

Link to my sheet with example

I've tried all option with built-in function, I'm expecting to know and understand a possible solution using AppScript

In your situation, how about the following sample script?

Sample script:

Please copy and paste the following script to the script editor of Spreadsheet and save the script. And please confirm the sheet names again.

function myFunction() {
  // Retrieve sheets.
  const ss = SpreadsheetApp.getActiveSpreadsheet();
  const productionSheet = ss.getSheetByName("Production");
  const complaintsSheet = ss.getSheetByName("Complaints");

  // Retrieve values from sheets.
  const [h1, ...v1] = productionSheet.getDataRange().getValues();
  const range = complaintsSheet.getRange("A2:I" + complaintsSheet.getLastRow());
  const [h2, ...v2] = range.getValues();

  // Create an array for putting to Complaints sheet by converting columns.
  const hconv = h2.map(h => h1.indexOf(h));
  const obj = v1.reduce((o, r) => (o[r[0]] = hconv.map(i => i > -1 ? r[i] : null), o), {});
  const len = Object.values(obj)[0].length;
  const res = v2.map(([a]) => obj[a] || Array(len).fill(null));

  // Put the created array to Complaints sheet.
  range.offset(1, 0, res.length, res[0].length).setValues(res);
}

• When this script is run, the values are retrieved from both sheets. And, an array is created for putting to "Complaints" sheet by checking the ID of column "A" and converting the columns. And, the array is put to "Complaints" sheet.

Note:

• In this sample, I tested it using your sample Spreadsheet. If you change the spreadsheet, this script might not be able to be used. Please be careful about this.

• I thought that in this case, the custom function might be able to be used. But, from your question, if the data is large, the custom function cannot be used. So, I proposed the above script.

• In this sample, in order to convert the columns, the header titles are used. So, if you change the header titles, please be careful about this.

• As another approach, if you want to put the value to the row when you put a value to the column "A" of "Complaints", how about the following script? In this script, the script is automatically run by a simple trigger of OnEdit. So, in this case, when you put a value to the column "A" of "Complaints" sheet, this script is automatically run, and the value is put into the edited row. Please select one of 2 scripts for your actual situation. As an important point, when you use this, please don't directly run this function because of no event object. Please be careful about this.

  function onEdit(e) {
    const { range, source } = e;
    const complaintsSheet = range.getSheet();
    if (complaintsSheet.getSheetName() != "Complaints" || range.columnStart != 1 || range.rowStart <= 2) return;
    const value = range.getValue();
    const productionSheet = source.getSheetByName("Production");
    const [h1, ...v1] = productionSheet.getDataRange().getValues();
    const [h2] = complaintsSheet.getRange("A2:I2").getValues();
    const hconv = h2.map(h => h1.indexOf(h));
    const obj = v1.reduce((o, r) => (o[r[0]] = hconv.map(i => i > -1 ? r[i] : null), o), {});
    const len = Object.values(obj)[0].length;
    const res = [obj[value] || Array(len).fill(null)];
    range.offset(0, 0, res.length, res[0].length).setValues(res);
  }
  

References:

• reduce()
• map()