Underscore.js或CoffeeScript习惯用法，用于查询多个对象键？

Question

I have a parsed query string object, req.query , and I want to see if that object has any of three keys: foo , bar , baz .

Is there an idiomatic way of querying that with Underscore and/or CoffeeScript?

# simple and direct but not very DRY:
if req.query.foo or req.query.bar or req.query.baz
  ..

# using the any filter combined w/ CS's in sugar:
if _(req.query).any (val, key) -> key in ['foo', 'bar', 'baz']
  ..

# plucking just the desired keys:
if _(req.query).pick('foo', 'bar', 'baz').keys().length
  ...

Is there another way better than any of these? Either way, what would you write?

Answer 1

How about using pick ?

if !_.isEmpty(_(req.query).pick("foo", "bar", "baz"))
  ...

Answer 2

How about:

queryKeys = _.keys(req.query)
if _(queryKeys).intersection(['foo', 'bar', 'baz']).length
  ...

Answer 3

Some alternatives:

# Helper function:
# ----------------
_has = (obj, arr) -> (1 for key in arr when obj.hasOwnProperty(key)).length > 0

if _has req.query, ['foo', 'bar', 'baz']
    ...

# Extending `Object`:
# -------------------
Object::has = (arr) ->
    while arr.length && not result = @hasOwnProperty arr.shift() then
    result

if req.query.has ['foo', 'bar', 'baz']
    ...

# Using native `Array::some`:
# ---------------------------
if ['baz', 'bar', 'foo'].some {}.hasOwnProperty.bind req.query
    # ...

Actually I would write this:

if (true for key in ['foo', 'bar', 'baz'] when req.query[k]).length

but only if the list is longer than that, otherwise the simple if query.foo or query.bar or query.baz wins for clarity and efficiency.