Nest array within another array?

JavaScript
1

Hello.

I’ve got this code:

const myStorage = {
  "car": {
    "inside": {
      "glove box": "maps",
      "passenger seat": "crumbs"
     },
    "outside": {
      "trunk": [
        "jack",
        "blanket",
        "hamper",
        "tool box" : [
          "hammer",
          "screwdriver",
          "Monkey spanner"
        ]
      ]
    }
  }
};

The part I’m having trouble with is this:

      "trunk": [
        "jack",
        "blanket",
        "hamper",
        "tool box" : [
          "hammer",
          "screwdriver",
          "Monkey spanner"
        ]

I’m trying to nest a new array called “tool box” inside the “trunk” array.

I can (kind of) see why it doesn’t work (that semi-colon is to do with objects, not arrays), but can’t find a way of doing this.

Can any one point out what I should be doing? Or tell me whether it can actually be done (that is, have a titled array within an array)?! :slight_smile:

2

You can put an array in another array, but that’s not exactly what you’re attempting here.

"tool box" : [
          "hammer",
          "screwdriver",
          "Monkey spanner"
        ]

This is an object property with a key and a value, which you can’t put in as an array item.

3

Hi, yes, I mentioned that in my post.

Trying to figure out how to do it.

Just come up with this - it works (I can access e.g. ‘hammer’, ‘screwdriver’ etc) but feel it’s not quite there…What do you think?

      "trunk": [
        "jack",
        "blanket",
        "hamper",
        ["toolbox", [
         "hammer",
          "screwdriver",
          "Monkey spanner"
        ]],
      ]
4

If you want toolbox to be in an object, you can make the object be an item in the array.

// array of mixed types
let myArr = [
    'string',
    999,
    ['I', 'am', 'an', 'array'],
    { name: 'object property'},
    true
]
5

Thanks but how would I access e.g. “hammer”?

In my example

      "trunk": [
        "jack",
        "blanket",
        "hamper",
        ["toolbox", [
         "hammer",
          "screwdriver",
          "Monkey spanner"
        ]],
      ]

I can get it by e.g.:

const toolBoxContents = myStorage.car.outside.trunk[3][1][0]
console.log(toolBoxContents) /* hammer */

Can’t figure out a way to reference it from the object:

      "trunk": [
        "jack",
        "blanket",
        "hamper",
        {
          "toolbox": [
            "hammer",
            "screwdriver",
            "Monkey spanner"
          ]
        }
      ]
6

In that example, “hammer” would be trunk[3].toolbox[0].

I wouldn’t particuluarly suggest building a collection this way, and if this is an FCC challenge, I suspect that you misread a part of the instructions.

7

I see, thanks for your help!

Your suspicions are unfounded - didn’t misread anything - just playing around with code.

8

Glad to help. Playing around with the code is, IMHO, the best way to learn how it works. I just didn’t want you to get frustrated thinking that this convoluted lookup method was required for the challenge. Happy coding!

9

Thanks again!

As you say this wouldn’t be a way to build a collection, any pointers to the correct way of achieving my aim (which is to have a sub array with a title inside a parent array)?

10

Since array items are accessed by index, not by name, adding a name to a sub-array doesn’t really gain you anything.

// It isn't uncommon to have an array of objects: 
const users = [
  { username: 'ArielLeslie', isAwesome: true },
  { username: 'najccforum', isAwesome: true },
  { username: 'SpammySpammer', isAwesome: false }
];
// Then you can iterate over it
for (let i = 0; i<=users.length; i++) {
  if (users[i].isAwesome) {
    console.log('Hooray for ' + users[i].username + '!');
  }
}

// or you might have an object of arrays
const flavors = {
  iceCream: ['chunky monkey', 'vermonty python'],
  cookies: ['chocolate chip', 'snickerdoodle', 'peanut butter'],
  salads: ['sadness']
}; 
// then you can look the items up by name
function printFlavors(foodType) {
  console.log('The available flavors of ' + foodType + ' are: ' + flavors[foodType].join(' and '));
}
1 Like
11

{ username: 'najccforum', isAwesome: true }
:slight_smile:

Thanks for all your help!