120 lines
3.7 KiB
JavaScript
120 lines
3.7 KiB
JavaScript
#!/usr/bin/env node
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const fs = require('fs').promises;
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const process = require('process');
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const puppeteer = require('puppeteer');
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// Size of the rendering of the web page
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const size = { width: 1280, height: 720 };
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async function main() {
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if (process.argv[2] === undefined) {
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console.error('This program expects an argument.');
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console.error('USAGE: locator <path-to-HTML-file>');
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process.exit(1);
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}
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// Path to the HTML file to analyse (given as relative path from current directory)
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// We need the full path so that puppeteer is able to access it
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const path = process.argv[2].startsWith('/') ? process.argv[2] : process.cwd() + '/' + process.argv[2];
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// Check that the file exists
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try {
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await fs.access(path, fs.constants.F_OK);
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} catch (e) {
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console.error('No such file: ' + path);
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process.exit(1);
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}
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// Initialize browser
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const browser = await puppeteer.launch();
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const page = await browser.newPage();
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await page.setViewport(size);
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await page.goto('file://' + path);
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// Only consider the first slide (#\\331 === #1, which is the id of the first slide)
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// We don't take into account the other slides because it will mess up with our screenshot varification
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let root = await page.$('#\\31');
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// Take a first screenshot
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await page.screenshot({path: __dirname + '/' + 'screenshot1.png'});
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// Edit the page to shrink elements in order to get better bounding boxes
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let withSpan = await addSpan(root);
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// Take another screenshot and check the modification we made didn't change the layout of the page
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await page.screenshot({path: __dirname + '/' + 'screenshot2.png'});
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// Compare both screenshots
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let file1 = await fs.readFile(__dirname + '/' + 'screenshot1.png');
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let file2 = await fs.readFile(__dirname + '/' + 'screenshot2.png');
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let filesAreSame = file1.map((x, i) => x === file2[i]).reduce((a, b) => a && b, true);
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// Crash if they're different
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if (!filesAreSame) {
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throw new Error("Page edit changed the layout");
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}
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// Analyse the root and output the result
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let analyse = await analyseElement(root);
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console.log(JSON.stringify(analyse, undefined, 4));
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await browser.close();
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}
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// Traverses the text nodes of the element and put every text into a single span.
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async function addSpan(element) {
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let elts = await element.$$('*');
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for (let elt of elts) {
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let value = await elt.evaluate(el => el.textContent, element);
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if (value !== "") {
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await elt.evaluate(el => el.innerHTML = '<span>' + el.innerHTML + '</span>');
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}
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}
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}
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// Recursive function to analyse an HTML element.
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// The output is written in hierarchy.
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async function analyseElement(element) {
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// Get some information on the element
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let tagAttr = await element.getProperty('tagName');
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let tagName = await tagAttr.jsonValue();
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let classAttr = await element.getProperty('className');
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let className = await classAttr.jsonValue();
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let textContent = await element.evaluate(el => el.textContent, element);
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let box = await element.boundingBox();
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// Register it into the return value
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let analyse = {};
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analyse.tag = tagName;
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analyse.class = className;
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analyse.box = box;
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analyse.children = [];
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// Extract the text content if it is a span (we made those spans by ourselves in the addSpan function)
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if (tagName === 'SPAN' && textContent !== "") {
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analyse.text = textContent;
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}
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// Select the children of this HTML element.
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let children = await element.$$('> *');
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for (let child of children) {
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// Recursively analyse the children
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analyse.children.push(await analyseElement(child));
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}
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return analyse;
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}
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main();
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