Make it work without requiring Symbol polyfill

[andreypopp]

The best would be to have babel to transpile Symbol itself.

[gaearon]

Same for Reflect

[chicoxyzzy]

so babel will add local polyfill but target browsers could be Symbol-ready. so we loose in performance and module size in that case

[sebmck]

Why use the symbol at all?

Just change:

return {
  configurable: true, // must be true or we could not be changing it
  get() {
    if (!this.hasOwnProperty(_key)) {
      this[_key] = fn.bind(this);
    }
    return this[_key];
  }
};

to

return {
  configurable: true, // must be true or we could not be changing it
  get() {
    var fn = this[key].bind(this);
    Object.defineProperty(this, key, {
      configurable: true,
      writable: true,
      value: fn
    });
    return fn;
  }
};

The current way is slower too since the overhead of the getter is going to be there every single time, regardless of your use of the private bound method.

[andreypopp]

@sebmck you are right, that's actually how it was implemented initially fb29744#diff-1fdf421c05c1140f6d71444ea2b27638