DisguisedMysteriousNormalform created by anonrose - https://repl.it/@anonrose/DisguisedMysteriousNormalform

index.js

let prom = new Promise(res => {
  res(5)
});

let assign = function(scope, variableName) {
  return (result) => {
    scope[variableName] = result;
  }
}

class Foo {
  constructor() {
    prom.then(assign(this, 't'));
  }
}

foo = new Foo();

setTimeout(() => {
  console.log(foo.t)
}, 50)

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