puppeteer/examples/unrandomize.js

/**
 * Copyright 2017 Google Inc., PhantomJS Authors All rights reserved.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

var Browser = require('../lib/Browser');
var browser = new Browser();

browser.newPage().then(async page => {
    await page.evaluateOnInitialized(function() {
        Math.random = () => 42 / 100;
    });
    var result = await page.navigate('http://ariya.github.com/js/random/');
    if (result) {
        console.log(await page.evaluate(function () {
            return document.getElementById('numbers').textContent;
        }));
    } else {
        console.log('Network error.');
    }
    browser.close();
});