Question

I have an object which I’m trying to get the last value of every key and put it into another object.

var setA = {
    'a':'001, 007, 101',
    'b':'052, 004, 006, 005',
    'c':'003, 002, 001'
}

What I’m trying to do is get the last ones like this:

var setB = {
    'a':'101',
    'b':'005',
    'c':'001'
}

How might I accomplish this?

Answer 1

Why not just:

var setB = {
    'a':setA.a.split(',').pop().trim(),
    'b':setA.b.split(',').pop().trim(),
    'c':setA.c.split(',').pop().trim()
}

JS Fiddle demo.

Effectively this takes the value returned from the variable in setA.a (and so on…), splits that string, at the , characters, into an array, pops off the last value of that array and trims the whitespace from it.

The following was raised from jbabey‘s answer, when I remembered that a string could be treated as an array of characters:

var setA = {
    'a': '001, 007, 101',
    'b': '052, 004, 006, 005',
    'c': '003, 002, 001'
},
    setB = {
    'a': setA.a.slice(-3),
    'b': setA.b.slice(-3),
    'c': setA.c.slice(-3)
}

console.log(setB);​

JS Fiddle demo.

References:

• pop().
• slice().
• split().
• trim().