TSDoc | TSDoc

When set to true, TypeScript will raise an error when a class property was declared but not set in the constructor.

// @errors: 2564
class UserAccount {
  name: string;
  accountType = "user";

  email: string;
  address: string | undefined;

  constructor(name: string) {
    this.name = name;
    // Note that this.email is not set
  }
}

// @errors: 2564
class UserAccount {
  name: string;
  accountType = "user";

  email: string;
  address: string | undefined;

  constructor(name: string) {
    this.name = name;
    // Note that this.email is not set
  }
}

In the above case:

this.name is set specifically.
this.accountType is set by default.
this.email is not set and raises an error.
this.address is declared as potentially undefined which means it does not have to be set.