New rule to warn about the usage of this keyword inside static class methods

Take a look at this silly class

class Rectangle {
  constructor(width, height) {
    this.width = width;
    this.height = height;
  }
  getArea() {
    return this.width * this.height;
  }
  static getHeight() {
    return this.height();
  }
}

This is valid JS while it has a lot of danger in it. I suggest the creation of a rule that prevents people from calling this from inside static class methods.

I would even suggest that eslint default config should give a warning on this.

[ljharb]

Since that syntax is required for symbols, a first-class language feature, i don’t think it makes sense to ever ban computed properties.

[not-an-aardvark]

I think it could be useful to have a rule that warns when:

• A class does not have a superclass (i.e. it doesn’t use the extends keyword)
• this.someMethod() is used in a static method of that class
• someMethod is not a static method of the class, and there are no static computed method names

That seems like it would be able to catch most error cases, without any false positives except when methods are added to a class after-the-fact.