decorators run in unexpected order

[trusktr]

This is unexpected and unintuitive:

function signal(_, context) {
  console.log('@signal decorator', context.name)
}

function memo(_, context) {
  console.log('@memo decorator', context.name)
}

class My {
  @signal a = 1
  @signal b = 2

  @memo get sum() {
    return this.a + this.b
  }
}

typescript playground, babel repl

Output:

@memo decorator sum
@signal decorator a
@signal decorator b

Every time I want to do something extremely simple, like rely on ordering of definitions so I can simply initialize storage in that order, I can't.

Decorators always want me to go to extravagant lengths to achieve otherwise simple concepts.

---

Or is this a bug in both TypeScript and Babel?

The proposal-decorators README here says this:

Decorators are evaluated as expressions, being ordered along with computed property names. This goes left to right, top to bottom.

With or without that description, I'd expect this output:

@signal decorator a
@signal decorator b
@memo decorator sum