On Nov 20, 2011, at 8:12 AM, Rick Waldron wrote:

> Ah, yes and agreed. That was definitely not relayed in the message below- 
> thanks for the clarification, the context does make a difference.

Destructuring parameters + default values really shine here:

  function frob(arg1, arg2, {foo = defFoo, bar = defBar, baz = defBaz}) {
    // just use foo, bar, and baz instead of ops.foo, etc.
  }

instead of the song and dance cited below.

/be



> 
> Rick
> 
> On Nov 20, 2011, at 1:40 AM, David Herman <dher...@mozilla.com> wrote:
> 
>> On Nov 19, 2011, at 5:50 PM, Brendan Eich wrote:
>> 
>>> On Nov 19, 2011, at 2:20 PM, Rick Waldron wrote:
>>> 
>>>> Q. We don't use option parameter like that in JS (see previous point for 
>>>> actual example)
>>>> 
>>>> Using an object-as-option parameter is a very common API design pattern in 
>>>> real-world JavaScript today - why anyone would say otherwise is 
>>>> confounding. 
>>> 
>>> Right. For example, ES5's property descriptor and property descriptor map 
>>> parameters.
>> 
>> It was me. I didn't say JS doesn't use options objects. I said the G11n 
>> library was using them wrong. They were doing:
>> 
>>     if (!ops) {
>>         ops = { foo: defFoo, bar: defBar, baz: defBaz };
>>     }
>> 
>> instead of e.g.:
>> 
>>     if (!ops)
>>         ops = {};
>>     if (typeof ops.foo === "undefined")
>>         ops.foo = defFoo;
>>     if (typeof ops.bar === "undefined")
>>         ops.bar = defBar;
>>     if (typeof ops.baz === "undefined")
>>         ops.baz = defBaz;
>> 
>> IOW, it shouldn't be all or nothing, but rather each property of the options 
>> object is separately optional.
>> 
>> Dave
>> 

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