Designing a MultiMap (in DOM, would like to be consistent with ES)

Kris Kowal kris.kowal at
Fri Nov 30 16:07:54 PST 2012

Perhaps consider .push(key, …values) instead of .append(key, value)
and .appendAll(key, values).

I’ve seen this kind of MultiMap around, so I presume people like the
heterogenous range type. I’ve gone a different way in my work, where
MultiMap was a Map that would set the value for a missing key to an
empty array. Then, extended Array to have a "one" or "only" method.

getAll(key) ~ get(key)
get(key) ~ get(key).one()
setAll(key, values) ~ set(key, values)
set(key, value) ~ set(key, [value])
append(key, value) ~ get(key).push(value)
appendAll(key, values) ~ get(key).push(...values)

For the URL use case, this loses information about interleaving of
keys, which is usually unimportant except (perhaps) in making round
trips between parse and stringify.

Kris Kowal

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