diff --git a/README.md b/README.md index b74267b35f715..9c275b3439100 100644 --- a/README.md +++ b/README.md @@ -198,22 +198,28 @@ Puppeteer creates its own browser user profile which it **cleans up on every run displaying. Instead of launching in headless mode, launch a full version of the browser using `headless: false`: - const browser = await puppeteer.launch({headless: false}); + ```js + const browser = await puppeteer.launch({headless: false}); + ``` 2. Slow it down - the `slowMo` option slows down Puppeteer operations by the specified amount of milliseconds. It's another way to help see what's going on. - const browser = await puppeteer.launch({ - headless: false, - slowMo: 250 // slow down by 250ms - }); + ```js + const browser = await puppeteer.launch({ + headless: false, + slowMo: 250 // slow down by 250ms + }); + ``` 3. Capture console output - You can listen for the `console` event. This is also handy when debugging code in `page.evaluate()`: - page.on('console', msg => console.log('PAGE LOG:', msg.text())); + ```js + page.on('console', msg => console.log('PAGE LOG:', msg.text())); - await page.evaluate(() => console.log(`url is ${location.href}`)); + await page.evaluate(() => console.log(`url is ${location.href}`)); + ``` 4. Use debugger in application code browser @@ -223,7 +229,9 @@ Puppeteer creates its own browser user profile which it **cleans up on every run - Use `{devtools: true}` when launching Puppeteer: - `const browser = await puppeteer.launch({devtools: true});` + ```js + const browser = await puppeteer.launch({devtools: true}); + ``` - Change default test timeout: @@ -235,7 +243,9 @@ Puppeteer creates its own browser user profile which it **cleans up on every run - Add an evaluate statement with `debugger` inside / add `debugger` to an existing evaluate statement: - `await page.evaluate(() => {debugger;});` + ```js + await page.evaluate(() => {debugger;}); + ``` The test will now stop executing in the above evaluate statement, and chromium will stop in debug mode. @@ -248,10 +258,12 @@ Puppeteer creates its own browser user profile which it **cleans up on every run you want to try something out, you have to add it to your test file. - Add `debugger;` to your test, eg: - ``` + + ```js debugger; await page.click('a[target=_blank]'); ``` + - Set `headless` to `false` - Run `node --inspect-brk`, eg `node --inspect-brk node_modules/.bin/jest tests` - In Chrome open `chrome://inspect/#devices` and click `inspect`