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Nelio Alves
Nelio Alves

Reputation: 1371

Typescript - how to declare an attribute name started with @?

I'm trying to declare a type in TypeScript with an attribute named "@type" in order to correspond with some type from my Java API:

export interface Foo {
    id : string;
    name : string;
    @type: string;
}

However, I'm getting a compiler error in my VS Code.

Just to make sure it's not a JavaScript issue, I tried let test = JSON.parse('{"@type" : "value"}') in the browser console and it works fine.

So how can I declare such a type with an attribute name started with @?

Upvotes: 3

Views: 1832

Answers (1)

Arash Motamedi
Arash Motamedi

Reputation: 10682

Javascript (and Typescript) have relatively liberal member naming rules; meaning that you can use uncommon characters and even space. But in order to do so, you need to encase them in quotes:

interface MyInterface {
    property1: string;
    "@property 2": string;
}

const myobj: MyInterface = {
    property1: "Value 1",
    "@property 2": "Value 2"
}

If you do use non-alphanumeric property names, you'd have to use the index syntax to access them:

console.log(myobj.property1); // Dot notation
console.log(myobj["@property 2"]); // Index notation

For more interesting and in-depth information, review Mathias Bynens' blog entries:

Upvotes: 7

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