@studnicky/lexical-this-only

Disallows an instance receiver from escaping its method. this.member and return this are allowed because they preserve the receiver's boundary. Aliasing, assigning, destructuring, storing, and passing an instance receiver to another function are reported.

Static context is different: there this is the constructor, so it may be used as a call or construction callee and passed as an argument for subclass-aware construction. The rule also allows an instance constructor to pass itself to one of its enclosing class's nested collaborators: new EnclosingClass.Nested(this) and new EnclosingClass.#Nested(this). Passing an instance to any other class or function remains an escape.

Fixable: No · Options: No · Suggested severity: error

✗ Incorrect

const self = this;
setTimeout(function() { self.run(); }, 100);

const that = this;
doAsync(() => { that.complete(); });

class Worker {
  public connect(): void {
    register(this);
  }
}

✓ Correct

// Arrow function preserves lexical this
setTimeout(() => { this.run(); }, 100);

// Arrow callback — no alias needed
doAsync(() => { this.complete(); });

class Base {
  public static create<T extends Base>(this: new () => T): T {
    return new this();
  }
}

class Owner {
  public attach(): void {
    new Owner.Nested(this);
  }

  public static Nested = class {
    public constructor(owner: Owner) {}
  };
}