Wait till page stopped with puppeteer

util.ts

// tslint:disable: no-console
import * as BlinkDiff from "blink-diff";
import { Page } from "puppeteer";

export function sleep(ms: number) {
  return new Promise((resolve) => setTimeout(resolve, ms));
}

export async function waitTillPageStoped(
  page: Page,
  interval: number = 200,
  timeout: number = 3000,
  fullPage: boolean = true,
): Promise<boolean> {
  const t0 = new Date().getTime();
  let previousBuffer: Buffer;
  while (new Date().getTime() - t0 < timeout) {
    await sleep(interval);

    const currentBuffer: Buffer = Buffer.from(await page.screenshot({
      encoding: "base64",
      fullPage,
    }), "base64");
    if (previousBuffer == null) {
      previousBuffer = currentBuffer;
      continue;
    }

    const diff = new BlinkDiff({ imageA: previousBuffer, imageB: currentBuffer });
    const result = await diff.runWithPromise();
    if (result.differences === 0) {
      return true;
    }

    previousBuffer = currentBuffer;
  }

  throw new Error("Timeouted!!");
}