Unconventional way of assigning class properties in Typescript (Javascript): '?='

Question

Unconventional way of assigning class properties in Typescript (Javascript): '?='

Recently, I came across the ?= assignment expression within a class property declaration. Can anyone provide some insight into what this means?

I am familiar with the new Optional Chaining feature (object?.prop), but this particular syntax is unfamiliar to me. I am unsure if it is a mistake or an actual language feature?

export class GoogleConfig {
  GOOGLE_CLIENT_ID: string
  GOOGLE_CLIENT_SECRET: string
  GOOGLE_CALLBACK_URL?='http://localhost/frontend'
  GOOGLE_CALLBACK_URL_INTERNAL?='http://localhost/auth/google'
}

Any clarification on this matter would be greatly appreciated!

javascript typescript expression

Answer 1

Answer №1

Standard practice dictates that properties defined within an interface are compulsory, however, you have the ability to designate a property as optional by adding a ?:.

class Configuration {
    name: string;
    size?: number;
    color?: string;
}

In this example, the name field is mandatory while the rest are considered optional.

Answer 2

Standard practice dictates that properties defined within an interface are compulsory, however, you have the ability to designate a property as optional by adding a ?:.

class Configuration {
    name: string;
    size?: number;
    color?: string;
}

In this example, the name field is mandatory while the rest are considered optional.

Answer 3

Answer №2

Looks like a class property that is possibly optional and lacks a specified type

export class GoogleConfig {
  GOOGLE_CLIENT_ID: string
  GOOGLE_CLIENT_SECRET: string
  GOOGLE_CALLBACK_URL?:string ='http://localhost/frontend'
  GOOGLE_CALLBACK_URL_INTERNAL?:string ='http://localhost/auth/google'
}

Answer 4

Looks like a class property that is possibly optional and lacks a specified type

export class GoogleConfig {
  GOOGLE_CLIENT_ID: string
  GOOGLE_CLIENT_SECRET: string
  GOOGLE_CALLBACK_URL?:string ='http://localhost/frontend'
  GOOGLE_CALLBACK_URL_INTERNAL?:string ='http://localhost/auth/google'
}

Unconventional way of assigning class properties in Typescript (Javascript): '?='

Answer №1

Answer №2

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