JS: Nested for loop while parsing JSON

Question

for (kind in animals) {
  content += animals[kind][0].name + '<br>';
}

This returns the first name of each animal kind from my JSON. I'm struggling to get ALL names rather than just [0]. Since there doesn't appear to be a simple wildcard like [*], I tried putting a second for loop inside the first one like so:

for (var kind in animals) {
  for (var i in kind) {
    content += animals[kind][i].name + '<br>';
  }
}

But as it should, that simply doesn't work.

I know this is easily accomplished with something like Underscore.JS but I would really like to do it with just pure vanilla.

Have you tried structuring your second for loop to look like this: for(var i in animals.kind){}? — Robert
– Robert, Commented Jul 31, 2015 at 16:21
Whats your JSON structure look like? The first example makes it look mile a 2-d array, the second makes it look like and array of objects. — Dylan Watt
– Dylan Watt, Commented Jul 31, 2015 at 16:22
kind is a key (property name). But you use it as object which is wrong — hindmost
– hindmost, Commented Jul 31, 2015 at 16:23
Basically, here's a stripped version. {"cat": [ {"name": "Wilbur"}, {"name": "Stella"} ], "horse": [ {"name": "Bob"}, {"name": "Jesse"} ] } — user4513271
– user4513271, Commented Jul 31, 2015 at 16:25

hindmost · Accepted Answer · 2015-07-31 16:27:42Z

2

AFAIU animals[kind] is an array. In this case you can use forEach instead of nested loop (which is wrong in your code).

for (var kind in animals) {
  animals[kind].forEach(function(v) {
    content += v.name + '<br>';
  });
}

answered Jul 31, 2015 at 16:27

hindmost

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Comments

user663031 · Accepted Answer · 2015-07-31 16:38:38Z

0

When you refer to the name in the content += line, you correctly use animals[kind], but you also need to specify that as the thing to be looped over. kind is just the property, what you want to loop over is the array held by animals[kind]:

for (var kind in animals) {
  for (var i in animals[kind]) {
                ^^^^^^^^^^^^^
    content += animals[kind][i].name + '<br>';
  }
}

It's considered bad practice to use for...in to loop over arrays, for for the purposes of this question, that's not the important thing.

answered Jul 31, 2015 at 16:38

user663031

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