Await is only valid in async function with nodejs

The answers suggesting to make the callback async will make the error disappear, but the overall readFile operation will not be awaited. So, if for instance, you would enable the line with await browser.close();, that browser.close() will run before the readFile callback executes.

When you use promises, you are better off using the Promise API for fs:

const fsPromises = require('fs').promises; const handle = await fs.readFile('db.txt'); const data = await handle.readFile(); let array = data.toString().split("\n"); // ...etc await handle.close(); 

This way:

• You don't have a callback, and you can use await with the file and other asynchronous operations
• The main async function's returned promise will only resolve when all await-tasks have been performed.

the callback function inside fs needs to be async as well

this part : fs.readFile('db.txt', async function (err, data)

const puppeteer = require("puppeteer"); const fs = require('fs'); let galleryName = "frozen"; // Enter gallery name (async () => { const browser = await puppeteer.launch(); const page = await browser.newPage(); // Adjustments particular to this page to ensure we hit desktop breakpoint. page.setViewport({ width: 1000, height: 10000, deviceScaleFactor: 1 }); fs.readFile('db.txt', async function (err, data) { if (err) throw err; let array = data.toString().split("\n"); for (i in array) { console.log(`Now Processing : ${array[i]} ${array.length - i -1} left`); await page.goto(`https://gall.dcinside.com/${galleryName}/${array[i]}`), { // !!!!ERROR shows from here waitUntil: "networkidle2", timeout: 0 }; async function screenshotDOMElement(opts = {}) { const padding = "padding" in opts ? opts.padding : 0; const path = "path" in opts ? opts.path : null; const selector = opts.selector; if (!selector) throw Error("Please provide a selector."); const rect = await page.evaluate(selector => { const element = document.querySelector(selector); if (!element) return null; const { x, y, width, height } = element.getBoundingClientRect(); return { left: x, top: y, width, height, id: element.id }; }, selector); if (!rect) throw Error( `Could not find element that matches selector: ${selector}.` ); return await page.screenshot({ path, clip: { x: rect.left - padding, y: rect.top - padding, width: rect.width, height: rect.height + padding * 2 } }); } await screenshotDOMElement({ path: `./result/${pageNumArray[i]}.png`, selector: ".view_content_wrap", padding: 10 }); } }); // // await browser.close(); })(); 

read more here about async-await' https://javascript.info/async-await

You have to use async inside callback function then only you can able to use await otherwise you'll get the error.

fs.readFile('db.txt', async (err, data) => { });