react typescript readonly props

I'm all for strongly typed, I mantain 6 projects all with strictNullChecks, but the benefits here are much smaller than the problems it currently produces.

It was published 01 Jan, 2021. I'm happy to defer to any of the reviewers for react in DefinitelyTyped (I cc'd them all above). If the app worked prior to the Readonly change, then after this change it stoped working and it gives no compile time errors. @pawelpabich No, this is not the place to have this argument. TypeScript solves these problems! It is more difficult to set types for them though. Our shop uses vscode to do any active typescript development and VS is used more to simply patch code files or for non-typescript developers to look through code, not necessarily for active development.

Learn on the go with our new app. Which of course will not work, regardless of Readonly. What happened to the topState property? @pawelpabich I agree my mannerisms were less than professional - but understandably so considering I gave you several explanations, samples, etc, and you choose not to listen to me. How did this note help previous owner of this old film camera? First of all we declare our initialState: Then we use Typescript to infer State type from our implementation. Its possible one day that Readonly will apply recursively, but for now, its on you to be sure you've handle it right.

So this change nowadays breaks all the VS and disables Go To Definition in all the VS Codes except if you have a plug-in Also there is the completeness argument. Thanks for reading! Did Sauron suspect that the Ring would be destroyed? @ericanderson I don't think we are making any progress here. did not help me get out of my hole.

privacy statement. furthermore, if it did work, then it would just be over-writing the state set by the parent.

How could you? In fact, the latest version of the typings doesn't even use the readonly keyword, so you can actually assign the state anywhere, just not change properties inside state. and this doesn't satisfy DerivedState OR BaseProps. The issue we were talking about here was a bug with the typescript compiler that caused the state properties to lose their types in inherited components.

: () => void; } If it is defined as function it gives following error. as something like: `{ values: Map }` and read @caesay I fully agree that if there are no constraints then the assignment does not make sense. First we need to create HOC that wrap our component with loading logic. error. Your code will always suffer the need to change once you get the update that finally marks state as Readonly<>.

These types of non-deterministic CI failures are troubling.

I'm not sure the lack of expressivity of the compiler makes the typings "wrong". in our experience, VS is always a little behind. React components watch this observable for events and funnel those events into a call to forceUpdate (after debouncing). [if you want to handle the state in your derived component] you can add a protected member getBaseState() and call this from the derived constructor when you set the state. Is it against the law to sell Bitcoin at a flea market? this.setState(map); Below is an example component. Type 'Function' is not assignable to type 'EventHandler> | undefined'. You are fundamentally wrong in your understanding of the language. Also because we are using typescript and we mapped State to be explicitly read-only, it will prevent us to do any mutations within those functions as well. More important, if you make abstract component like this: TS is able to show that there is a property onChange, but sometimes can not discover his type. When should it be released into DefinitelyTyped?

If you are convinced this is what you want, you can add a protected member getBaseState() and call this from the derived constructor when you set the state (so you don't have to duplicate the base state logic). @patsissons I may be wrong, but I believe SemVer is designed to be backwards compatible with APIs and semantic intents. "Selected/commanded," "indicated," what's the third word? I will write a summary of useful code snippets with React + TypeScript. This is the most important change since if prevents me to have hierarchies of components that share common props and functionality.

These state objects contain multiple rxjs observable streams that funnel into a notification observable called stateChanged. If you think closing this issue is a mistake, please pop into the TypeScript Community Discord and mention the issue in the definitely-typed channel.

const WrappedCounter = counterFactory(Counter). Working example of how this would be done: If the app worked prior to the Readonly change, then after this Like freeze. Your props in base in the constructor is not typed. `this.state.values.get('aKey')` Below is an example component.

Sign up for a free GitHub account to open an issue and contact its maintainers and the community. It looks like a problem in TS compiler but until it's fixed. I'm on TS 2.4.1.

I'm curious about other peoples thoughts on how DefinitelyTyped should work with respect to tooling updates as well as philosophy about Readonly on react (and other libraries whose intent is that you dont modify certain objects). rev2022.7.21.42639.

Otherwise it is hard to have a discussion. By doing this we dont have to maintain types and implementation separately, we have a single source of truth, which is the implementation. In each case you are literally trying to assign.

By explicitly mapping our type State to readonly via Readonly and setting readonly state within our class component, TS will let us know that we are doing something wrong immediately. On the other side, the change of setState is great , didn't know about Pick.

State should always be a plain keyed object afaik, so instead define state I ageee that where Readonly should be used is not 100% defined.

TS + React - Should props interfaces be exported? We need to be explicit again and define our State type to define state property on the class. It is exported so it can be used by the component that the HOC wraps: We use a generic here and this time it ensures that the component passed into the HOC includes the props that are going to be injected by it. @patsissons and @ericanderson focused on the problem and now we have a solution that others can use. You can always call setState (in componentWillMount). For example, setState used to take S which meant to do partials we used to have to do weird tricks like setState({foo:5} as any as State) or use the one that takes a function. The react guide in fact tells you not to update state directly: https://facebook.github.io/react/docs/state-and-lifecycle.html#do-not-modify-state-directly. Either way its not an argument for their inclusion. Vue.js for example promotes the imperative changes, I won't be surprised if it influences React. What @patsissons did was take the comments already mentioned here and provide a code sample - which shouldn't have been necessary.

You can assign to readonly variables in the constructor, and Readonly doesn't prevent assignment (ever!). change it stoped working and it gives no compile time errors. In effect, our mutable state lives within the state, but the state itself and the members that exist in the state are all immutable. @olmobrutall we use forceUpdate to queue a render on the react side, driven from observable events on the state side. Thanks for contributing an answer to Stack Overflow! TProps extends BaseProps which means that TProps has at least the same members that BaseProps has. below is your example converted to a fully polymorphic solution, with complete separation of concerns with respect to state construction: @caesay I admit I was wrong and for some reason did not see that the assignments will override each other. React itself doesnt have strict type checking and on larger scale projects you wouldnt know what state shape you are working with or what the mysterious API response returns (unless you check it).

But following code still generates compilation errors though compiler has all required information to verify that the code is correct. The final state would be { baseState1: "fronBase" }. This has since been fixed I believe, and if so this issue can be closed. return loading ? To learn more, see our tips on writing great answers. Given that I think its better to push people towards the "right" thing, you can easily work around this issue by redeclaring public state: My issues are with the generics variance. Of course you could cast the state to S (or any) and make the change, but if it's a common pattern gets cumbersome. The Interleaving Effect: How widely is this used? public render() { What drives the appeal and nostalgia of Margaret Thatcher within UK Conservative Party?

It is defined like so: To understand why this is the case, you need to know that RefObject is returned by one of TypeScript's three overloads for the React useRef() hook, which are defined as follows: Where the MutableRefObject return type is defined as follows: If it's not already clear why and when we get the return type as RefObject, it is when: As you might have already guessed, you can fix this by simply making the result of useRef directly mutable. I am newbie in React and Typescript.In AlertDismissable class I am setting property of show when a request completed.I have used this sample and changed it a bit. since given the current state of type definition versioning a successive build with no source changes can break.