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Why can't the name of a JavaScript class constructor be set in a static initialization block?

The name property of a JavaScript class constructor is read-only once the class is defined, but it can be modified by a static field definition in the class body itself. However, I was surprised to find that it can’t be modified in a static initialization block.

This works great:

class Foo {
  static name = 'Bar';
}

But this throws a TypeError saying that name is read-only:

class Foo {
  static {
    this.name = 'Bar';
  }
}

Is this the intended behavior or an accidental quirk in the spec?

Tags:

2

Answers


  1. 0

    A static property declaration uses (internally) the Object.defineProperty() mechanism (well the internal version). Thus overriding the "name" property works there, because that won’t check "read-only" the way a normal property assignment does.

    Thus this will also work:

    class Foo {
  static {
    Object.defineProperty(this, "name", { value: 'Bar'});
  }
}
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  2. 0

    This piece of code will work just fine .The idea I suppose is that the static elements needs to be defined before you use the static initialization blocks.
    Read more here : https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Classes/Static_initialization_blocks

      class Foo {
    static name ;
    static {
        this.name = 'Bar1';
      }
  }
  console.log(Foo.name)
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