Sort array by order according to another array

Question

I have an object that is being returned from a database like this: [{id:1},{id:2},{id:3}]. I have another array which specified the order the first array should be

Answer 1

If you want linear time, first build a hashtable from the first array and then pick items in order by looping the second one:

data = [{id:5},{id:2},{id:9}]
order = [9,5,2]

hash = {}
data.forEach(function(x) { hash[x.id] = x })

sorted = order.map(function(x) { return hash[x] })

document.write(JSON.stringify(sorted))