POST data to Google Sheets using Google Scripts

Code.gs

// Original: https://mashe.hawksey.info/2014/07/google-sheets-as-a-database-insert-with-apps-script-using-postget-methods-with-ajax-example/

// Usage
//  1. Enter sheet name where data is to be written below
var sheetName = 'Users'      
//  2. Run > setup
//
//  3. Publish > Deploy as web app 
//    - enter Project Version name and click 'Save New Version' 
//    - set security level and enable service (most likely execute as 'me' and access 'anyone, even anonymously) 
//
//  4. Copy the 'Current web app URL' and post this in your form/script action 
//
//  5. Insert column names on your destination sheet matching the parameter names of the data you are passing in (exactly matching case)
var scriptProp = PropertiesService.getScriptProperties()

function setup () {
  const activeSpreadsheet = SpreadsheetApp.getActiveSpreadsheet()
  scriptProp.setProperty('key', activeSpreadsheet.getId())
}

function parseBody (event) {
  try {
    return JSON.parse(event.postData.contents)
  } catch (error) {
    throw new Error('Bad body data: ' + error.message)
  }
}

function doPost (event) {
  const lock = LockService.getScriptLock()
  lock.tryLock(10000)

  try {
    const doc = SpreadsheetApp.openById(scriptProp.getProperty('key'))
    const sheet = doc.getSheetByName(sheetName)
    
    if (!sheet) {
      throw new Error('Could not find Google Sheet named: ' + sheetName)
    }
    const body = parseBody(event)
    const headers = sheet.getRange(1, 1, 1, sheet.getLastColumn()).getValues()[0]
    const nextRow = sheet.getLastRow() + 1
    
    const newRow = headers.map(function(header) {
      return header === 'timestamp' ? new Date() : body[header]
    })

    sheet.getRange(nextRow, 1, 1, newRow.length).setValues([newRow])

    return ContentService
    .createTextOutput(JSON.stringify({ 'result': 'success', 'row': nextRow, 'data': body }))
      .setMimeType(ContentService.MimeType.JSON)
  }

  catch (error) {
    return ContentService
      .createTextOutput(JSON.stringify({ 'result': 'error', 'error': error }))
      .setMimeType(ContentService.MimeType.JSON)
  }

  finally {
    lock.releaseLock()
  }
}

main.js

const gscriptUrl = `https://script.google.com/macros/s/${scriptId}/exec`
const body = {
  name: 'Pterobyte',
  hobbies: 'data, actually, cant, be, an, array, dinosaurs',
  meta: {
    objects: 'turn',
    out: 'pretty',
    weird: 'too'
  }
}
const fetchOptions = {
  method: 'POST',
  body: JSON.stringify(body)
}

fetch(gscriptUrl, fetchOptions)
  .then(res => res.json())
  .then(console.log)
  .catch(console.error)