docs(api.md): add notes on race condition in page.setViewport #4319
Conversation
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
docs/api.md
Outdated
| @@ -1799,6 +1804,20 @@ puppeteer.launch().then(async browser => { | |||
|
|
|||
| In the case of multiple pages in a single browser, each page can have its own viewport size. | |||
|
|
|||
| To avoid race condition with page's logic that sniffs for viewport properties, | |||
There was a problem hiding this comment.
This sounds like inside baseball. Can we phrase it in a way that will make more sense to puppeteer users? Is this a bug or intended behavior? What happens if I emulate after navigating? If its a bug where is the link?
This also implies that I can't use setViewport to simulate a resize event. Is that true?
docs/api.md
Outdated
| @@ -1799,6 +1804,20 @@ puppeteer.launch().then(async browser => { | |||
|
|
|||
| In the case of multiple pages in a single browser, each page can have its own viewport size. | |||
|
|
|||
| To avoid race condition with page's logic that sniffs for viewport properties, | |||
There was a problem hiding this comment.
page.setViewport will resize the page. A lot of websites don't expect phones to change size, so you should set the viewport before navigating to the page.
| @@ -1236,7 +1236,8 @@ Emulates given device metrics and user agent. This method is a shortcut for call | |||
| - [page.setViewport(viewport)](#pagesetviewportviewport) | |||
|
|
|||
| To aid emulation, puppeteer provides a list of device descriptors which can be obtained via the [`puppeteer.devices`](#puppeteerdevices). | |||
| Below is an example of emulating an iPhone 6 in puppeteer: | |||
|
|
|||
| `page.emulate` will resize the page. A lot of websites don't expect phones to change size, so you should emulate before navigating to the page. | |||
There was a problem hiding this comment.
This is even easier. The user agent needs to be sent before the first navigation.
There was a problem hiding this comment.
Fair! Keeping it as-is doesn't hurt.
JoelEinbinder
approved these changes
Jun 11, 2019
This was referenced Feb 3, 2020
This was referenced Feb 22, 2020
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
Fixes #2755.