defaultFieldResolver should bind source

[dimitri-koenig]

PR for this issue: defaultFieldResolver should bind source #979

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[papandreou]

Function#call is usually faster than Function#apply, and since you're not passing varargs here, it'd probably be better to go:

return source[info.fieldName].call(source, args, context, info);

[dimitri-koenig]

Fair enough, there we go with call instead of apply

[dimitri-koenig]

@papandreou Any more changes needed or is this PR ready to be merged?

[papandreou]

@dimitri-koenig, I'm not in charge here, so I don't know :)

[leebyron]

Thanks for your patience - could you please add unit tests for this?

I think this was always the intent, and was assuming that the source[method](arg) form would use source as this in the same way as the source.method(arg) form. This assumption is also behind why no-useless-call is being triggered. I'm curious to know if eslint is also wrong, if so we should make sure an issue is filed on that project.

Adding a test for this may help either confirm that the existing code does this, or if it failed with the existing code that this solution is the right fix. Either way, the test would be really valuable.

[dimitri-koenig]

I found the real issue, though I don't have an explanation for it:

In graphql-tools the same code is being used though an old version, where the call of the class method is being made like this:

return property(args, context);

Changing this to the code used right now works:

return source[info.fieldName](args, context, info);

So no need to change anything.