Typescript: Receiving errors when typing an object or array as rxjs Subject variable

Question

My snippet.

signUpInfo: {code: string, message: string} 
     = new Subject<{code: string, message: string}>();

The error Atom editor gives me.

Type 'Subject<{code: string, message: string}>' is not assignable to type '{code: string, message: string}'. Property 'code' is missing in type 'Subject<{code: string, message: string}>'.

Removing the typings in the variable, replacing by type any or {} removes the error.

signUpInfo = new Subject<{code: string, message: string}>();
signUpInfo: any = new Subject<{code: string, message: string}>();
signUpInfo: {} = new Subject<{code: string, message: string}>();
signUpInfo = new Subject<{code: string, message: string}>();
signUpInfo: any[] = new Subject<model[]>();

I am used to put a typeings on every variable in TS, I have no problems when passing regular types such as string number booleans etc. but when passing array or object as Subject variable typings it seems that Im not allowed to it.

What is the correct way of typing an object or array Subject variable in typescript?

A Subject<Message> is like a phone: it emits messages. A phone is not a message. The type of your variable should be the type you used on the right side of the equal sign: Subject<{code: string, message: string}> — JB Nizet
– JB Nizet, Commented Sep 10, 2017 at 17:34

martin · Accepted Answer · 2017-09-10 17:34:47Z

3

The correct way is to set:

signUpInfo: Subject<{code: string, message: string}> = new Subject<{code: string, message: string}>();

Actually I think you don't even need to set the type because it's automatically assumed when you're assigning it an instance of Subject<{code: string, message: string}>. So if you try to call signUpInfo.next(1) the compiler will throw a type error.

answered Sep 10, 2017 at 17:34

martin

97.4k26 gold badges205 silver badges237 bronze badges

Sign up to request clarification or add additional context in comments.

1 Comment

flyingpluto7 Over a year ago

Thank you now i get it why there are a lot subject variable snippets having no typings

Collectives™ on Stack Overflow

Typescript: Receiving errors when typing an object or array as rxjs Subject variable

1 Answer 1

1 Comment

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

1 Comment

Your Answer

Sign up or log in

Post as a guest

Related