CODEWITHSUNDEEP
coffeescript
Daniel D
Daniel D

Reputation: 3677

Querying an array of objects

Anyone have guidance on how to query an array of hashes in coffeescript?

For example, I have an array of hashes, each with a "name" and "setting":

[
  {"name":"color", "setting":"red"},
  {"name":"scale_min", "setting":"15"},
  {"name":"scale_type", "setting":"linear"},
  {"name":"x_axis_label", "setting":"Weeks"}
]

I want to find the element in this array where the hash "name" is "x_axis_label"

How can I easily do that with coffeescript?

I need some kind of value_for_key_in_object(key, object) function and figured if would be part of the lexicon...

Upvotes: 16

Views: 16363

Answers (4)

AA.
AA.

Reputation: 4606

I always prefer a 'multi language' solution over a 'idiomatic' solution. Thus you can to use Array.filter

data = [{"name":"color","setting":"red"},{"name":"scale_min","setting":"15"},{"name":"scale_type","setting":"linear"},{"name":"x_axis_label","setting":"Weeks"}]
find = (data.filter (i) -> i.name is 'x_axis_label')[0]
alert find.setting

Upvotes: 10

Larry Maccherone
Larry Maccherone

Reputation: 9523

If you going to do this repeatedly, always looking for things where the name equals something, then you are better off converting this from an array of maps to just a map where the key is the name.

data = [
  {"name":"color","setting":"red"}
  {"name":"scale_min","setting":"15"}
  {"name":"scale_type","setting":"linear"}
  {"name":"x_axis_label","setting":"Weeks"}
]

myMap = {}
for row in data
  myMap[row.name] = row.setting

alert(myMap['x_axis_label'])

Demo

Upvotes: 12

epidemian
epidemian

Reputation: 19229

If you happen to be using Underscore.js, you can use find:

xAxisLabel = _.find data, (datum) -> datum.name is 'x_axis_label'

Upvotes: 8

gen_Eric
gen_Eric

Reputation: 227280

I just hacked this up quickly:

data = [{"name":"color","setting":"red"},{"name":"scale_min","setting":"15"},{"name":"scale_type","setting":"linear"},{"name":"x_axis_label","setting":"Weeks"}]

find = (i for i in data when i.name is 'x_axis_label')[0]

alert(find.setting)

Demo

Upvotes: 33

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