toString() should return the same for #{b, a} as #{a, b}

[ajvincent]

Just an observation. Since #{a, b} is logically equivalent to #{b, a}, you'll need a test to make sure that they return the same stringification, and may indeed want to specify that stringifying a Record means the keys are in a particular order.

Maybe the same for toPrimitive, valueOf cases.

[littledan]

Yes, there will be no way to observe the differences. I'd expect toString() to print out the keys sorted in the same sort order we use for Reflect.ownKeys. I think this will become more clear when we have the draft spec text written, and just fall out of the semantics.

[rickbutton]

Whether or not Record has non-null prototype that can hold a toString method is still up for debate in issue #71, but I think the answer to this question is the same regardless. Serialization/stringification of Records and Tuples will be deterministic for the same input value, and a record's properties are ordered, so the semantics of JSON.stringify mean that this will naturally happen, we won't need to do anything special here.