Comments (6)
We'll update the dom definitions to be sensitive to string arguments.
from flow.
When performing a createElement('canvas') the type can be known from the string, but how would you annotate getElementById('mycanvas') to type as HTMLCanvasElement instead of HTMLElement?
from flow.
What I would like, would be to be able to do something like:
var canvas : HTMLCanvasElement = document.createElement('canvas');
var mycanvas : HTMLCanvasElement = document.getElementById('mycanvas');
In other words, createElement
and getElementById
would be polimorphic. I don't know if Flow supports such feature.
from flow.
+1
from flow.
Thank you for reporting this issue and appreciate your patience. We've notified the core team for an update on this issue. We're looking for a response within the next 30 days or the issue may be closed.
from flow.
createElement("canvas")
does currently return a HTMLCanvasElement
, so this issue is resolved.
@lbolla Regarding your comment about getElementById
returning a specific HTMLElement
subtype—Flow does not do that, and it is unsafe to do. Flow doesn't know what HTML the code will execute against, and therefore doesn't know anything more specific.
This is a great use case for dynamic type tests.
var canvas = document.getElementById("mycanvas");
if (canvas instanceof HTMLCanvasElement) {
// good to go -- type of canvas is refined this block
} else {
// error condition -- provide some useful debug info
}
I see this as a good thing. Flow is helping you out and directing you to add error handling to make your code safer.
from flow.
Related Issues (20)
- Relay + graphql literals HOT 11
- [homebrew] regression test failure with 0.226.0,0.227.0 HOT 2
- FLOW BUG: This is a misplaced error HOT 3
- The `experimental.ts_syntax` doesn’t seem to do anything HOT 2
- Parameters<> does not support optional params HOT 2
- Top level exports HOT 1
- flow strict should allow unclear types for generics HOT 6
- Regression in invalid-computed-prop detection HOT 7
- Flow hangs every now and then requires restarting HOT 4
- Component syntax is not enabled HOT 5
- Alternative defaultProps not working with component syntax HOT 1
- Ability to copy all files and not only JS files when stripping types using `flow-remove-types` HOT 5
- Component syntax & unreachable code HOT 1
- Add a setting to turn off type guard removal / mutation risk check
- There is a question about `user friends` under limited login. When using limited login, the app only [get the user friends's app scoped IDs (ASIDs).](https://developers.facebook.com/docs/facebook-login/limited-login/permissions/#key-considerations-user-friends) **Can we get brief details about these user friends**, such like name, avatar, etc. It seems like we can't use graph API under limited login any more.
- [Proposal] Mark state & prop arrays in components & hooks as readonly HOT 5
- React.ElementType not working for children HOT 1
- Default arguments in an object destructure aren't checked for string literal unions HOT 1
- Regression with incompatible-type detection HOT 2
- Internal error on double underscore function name HOT 2
Recommend Projects
-
React
A declarative, efficient, and flexible JavaScript library for building user interfaces.
-
Vue.js
🖖 Vue.js is a progressive, incrementally-adoptable JavaScript framework for building UI on the web.
-
Typescript
TypeScript is a superset of JavaScript that compiles to clean JavaScript output.
-
TensorFlow
An Open Source Machine Learning Framework for Everyone
-
Django
The Web framework for perfectionists with deadlines.
-
Laravel
A PHP framework for web artisans
-
D3
Bring data to life with SVG, Canvas and HTML. 📊📈🎉
-
Recommend Topics
-
javascript
JavaScript (JS) is a lightweight interpreted programming language with first-class functions.
-
web
Some thing interesting about web. New door for the world.
-
server
A server is a program made to process requests and deliver data to clients.
-
Machine learning
Machine learning is a way of modeling and interpreting data that allows a piece of software to respond intelligently.
-
Visualization
Some thing interesting about visualization, use data art
-
Game
Some thing interesting about game, make everyone happy.
Recommend Org
-
Facebook
We are working to build community through open source technology. NB: members must have two-factor auth.
-
Microsoft
Open source projects and samples from Microsoft.
-
Google
Google ❤️ Open Source for everyone.
-
Alibaba
Alibaba Open Source for everyone
-
D3
Data-Driven Documents codes.
-
Tencent
China tencent open source team.
from flow.