Find Apps Script mistakes before you run them.

Side by side

The editor, before and after.

The same code, captured with myFunction turned off and on. These examples show checks for repeated spreadsheet reads, malformed recipient values, and symbol autocomplete. No script was run.

01 Repeated spreadsheet reads02 Invalid recipient values03 All symbols & types

Spot a cell-by-cell read loop

The same range is read one cell at a time inside a loop.

range.getCell(row, 1).getValue()

Native Apps Script Same code · Extension off

With myFunction Performance check · MF90001

Inside the editor

The IDE layer Apps Script leaves out.

Native Apps Script provides basic autocomplete and tooltips. It does not warn about loops that risk execution timeouts, malformed literal parameters, or broken cross-file references. myFunction adds those checks.

Types for SpreadsheetApp, GmailApp, CalendarApp, and all 31 advanced Google services are generated from live Apps Script runtimes.

function readStatuses() {
  const sheet = SpreadsheetApp.getActiveSheet();
  const rows = 20;
  const range = sheet.getRange(2, 3, rows, 1);
  const statuses = [];

  for (let row = 1; row <= rows; row++) {
    statuses.push(range.getCell(row, 1).getValue());
  }

  return statuses;
}

function readStatuses() {
  const sheet = SpreadsheetApp.getActiveSheet();
  const rows = 20;
  const range = sheet.getRange(2, 3, rows, 1);
  const statuses = [];

  const myFunctionValues = range.getValues();
  for (let row = 1; row <= rows; row++) {
    statuses.push(myFunctionValues[row - 1][0]);
  }

  return statuses;
}

Value-level validation

A string can still be the wrong value.

Apps Script declares mail recipients, folder paths, and URLs as generic strings. myFunction checks literal values against the expected format (code 91003) and flags malformed email addresses, including inside comma-separated CC lists.

Captured in Apps Script Domain validation · MF91003

Cross-file type inference

Give untyped parameters useful types.

Apps Script functions without JSDoc leave parameters as untyped any. myFunction traces function calls across your project and offers a Quick Fix (TS7006) to infer parameter types from real usage and generate JSDoc annotations.

Captured in Apps Script Quick fix · TS7006

Limits

What myFunction cannot do.

NO Execute Apps Script functions

myFunction never runs your script. Running stays in the editor, in your hands.

NO Run tests for you

It can propose test code. Deciding to run it and reading the result remain yours.

NO Create versions or deployments

Versions and deployments are untouched. Published behavior changes only when you change it.

NO Apply changes without your choice

Quick fixes modify text in your open editor only when you choose to apply them. There is no auto-save or auto-apply mode.

Questions

Asked and answered.

Does myFunction run my Apps Script functions?

No. Running stays in the Apps Script editor, in your hands. myFunction reports diagnostics and offers quick fixes, but it never executes your script.

Does myFunction modify or save my project automatically?

No. Quick fixes change text in your open editor buffer only when you choose to apply them. myFunction never saves, deploys, or runs your code.

What does the language server add to the Apps Script editor?

Loop-batching checks for quota-heavy service calls, value validation for literal strings, cross-file project diagnostics, hover documentation, signature help, and quick fixes, based on how Apps Script services behave at runtime.