Allow defaultResolveFn to call methods on classes and bind source as "this"

[dimitri-koenig]

I have an issue with classes being compiled back to es5 using babel, where I have the default resolver call a method without having the source being bound to it.

E.x.:

class FooBar {
  get myFirstProperty() {
    return 'this works';
  }
  get mySecondProperty() {
    return this.someOtherProperty + ' works too';
  }
  myMethod({param1, param2}) {
    return this.someOtherProperty + ' somehow does not work because calling "someOtherProperty" on undefined';
  }
}

I found the issue in the implementation of "defaultResolveFn" where the "method" is called directly:

    const property = source[fieldName];
    if (typeof property === 'function') {
      return property(args, context);
    }

A change to this and everything works fine:

    const property = source[fieldName];
    if (typeof property === 'function') {
      return property.apply(source, [args, context]);
    }

I also tried to write a test for it but somehow with typescript it works without this change.

Is this an implementation issue, which could be fixed through this referenced PR or something else?

Thx
Best
Dimitri

[dimitri-koenig]

Should be fixed with this PR: graphql/graphql-js#980