== Why is this an issue?

``++readonly++`` properties can only be assigned in a class constructor or at the point of declaration. If a class has a property that's not marked ``++readonly++`` but is only set in the constructor, it could cause confusion about the property's intended use. To avoid confusion, such properties should be marked ``++readonly++`` to make their intended use explicit, and to prevent future maintainers from inadvertently changing their use.

=== Noncompliant code example

[source,javascript]
----
class Person {
  private _birthYear: number;  // Noncompliant
  constructor(birthYear: number) {
    this._birthYear = birthYear;
  }
}
----

=== Compliant solution

[source,javascript]
----
class Person {
  private readonly _birthYear: number;
  constructor(birthYear: number) {
    this._birthYear = birthYear;
  }
}
----

ifdef::env-github,rspecator-view[]

'''
== Implementation Specification
(visible only on this page)

include::../message.adoc[]

'''
== Comments And Links
(visible only on this page)

include::../comments-and-links.adoc[]

endif::env-github,rspecator-view[]