force function parameter keyword in TypeScript(Angular)

Question

I want make a function, let it can be called like

addPets('Dog', someEvent);

there has problem on first parameter, I need force keyword, maybe a enum or type, but I don't know how do force that?

example:

export enum PetType {
    Cat  = 'Cat',
    Dog  = 'Dog',
    Fish = 'Fish'
}

addPets('Dog', someEvent); // fine
addPets('Cat', someEvent); // fine
addPets('Cow', someEvent); // error, because PetType not have Cow

thank every help.

In my opinion, that parameter maybe don't need type checking — Pork Jackson
– Pork Jackson, Commented Dec 10, 2019 at 11:44
After all, this parameter is a default parameter and it is a string. If I use a type, I do n’t know how to implement it. — Pork Jackson
– Pork Jackson, Commented Dec 10, 2019 at 11:50
There is a jQuery example, .on ('click', ...), where the string 'click' is a valid value, while .on ('cow', ...) is not, similar to this. — Pork Jackson
– Pork Jackson, Commented Dec 10, 2019 at 11:53
You can create interface with string type but enum is more suitable here — Taras Yaremkiv
– Taras Yaremkiv, Commented Dec 10, 2019 at 13:12

uminder · Accepted Answer · 2019-12-10 10:44:53Z

2

You should declare the argument type in your function signature and invoke it using the PetType enum.

function addPets(petType: PetType, ...): void {
   ...
}

addPets(PetType.Cat, someEvent);
addPets(PetType.Dog, someEvent);

answered Dec 10, 2019 at 10:44

uminder

26.4k6 gold badges45 silver badges91 bronze badges

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

Collectives™ on Stack Overflow

force function parameter keyword in TypeScript(Angular)

1 Answer 1

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

Comments

Your Answer

Sign up or log in

Post as a guest

Related