如何在未知深度的物体中寻找价值？

Question

Firstly I will try to explain situation.

I have categories array of objects which contains deeper objects and looks like this:

/*
    Categories

    Object variables legend:
    n - name, u - ID, p - category picture,
    s - sub categories
*/
    var Categories = [
        {n:'Category',u:1,p:'http://#',s:[{n:'Sub category',u:4,s:[{n:'Sub sub category',u:5,s:[],items:['sku','sku2']},{n:'Sub sub category 2',u:6,s:[],items:['sku','sku2']},{n:'Sub sub category 3',u:7,s:[],items:['sku','sku2']}],items:['sku','sku2']},{n:'Sub category',u:4,s:[{n:'Sub sub category',u:5,s:[]},{n:'Sub sub category 2',u:6,s:[]},{n:'Sub sub category 3',u:7,s:[]}]},{n:'Sub category',u:4,s:[{n:'Sub sub category',u:5,s:[]},{n:'Sub sub category 2',u:6,s:[]},{n:'Sub sub category 3',u:7,s:[]}]}],items:['sku','sku2']},
        {n:'Category',u:2,p:'http://#',s:[{n:'Sub category',u:8,s:[{n:'Sub sub category',u:9,s:[],items:['sku','sku2']},{n:'Sub sub category 2',u:10,s:[],items:['sku','sku2']},{n:'Sub sub category 3',u:11,s:[],items:['sku','sku2']}],items:['sku','sku2']}],items:['sku','sku2']},
        {n:'Category',u:3,p:'http://#',s:[{n:'Sub category',u:12,s:[{n:'Sub sub category',u:13,s:[],items:['sku','sku2']},{n:'Sub sub category 2',u:14,s:[],items:['sku','sku2']},{n:'Sub sub category 3',u:15,s:[],items:['sku','sku2']}],items:['sku','sku2']}],items:['sku','sku2']}
    ];

So basically sub categories, can have unlimited depth.. Now I need to write a function which will return value of items, when I will provide ID (which is u).

How should I achieve that, I could write multiple 'for' loops if I would know what the depth is, but I don't.

Is there some kind filtering function which I could adapt for this task?

Answer 1

The first observation is that your Categories object is slightly irregular. Categories is a regular object which looks like an array, while the sub-categories are all arrays.

This would make it easier to work with:

var Categories = [
        {n:'Category',u:1,p:'http://#',s:[{n:'Sub category',u:4,s:[{n:'Sub sub category',u:5,s:[],items:['sku','sku2']},{n:'Sub sub category 2',u:6,s:[],items:['sku','sku2']},{n:'Sub sub category 3',u:7,s:[],items:['sku','sku2']}],items:['sku','sku2']},{n:'Sub category',u:4,s:[{n:'Sub sub category',u:5,s:[]},{n:'Sub sub category 2',u:6,s:[]},{n:'Sub sub category 3',u:7,s:[]}]},{n:'Sub category',u:4,s:[{n:'Sub sub category',u:5,s:[]},{n:'Sub sub category 2',u:6,s:[]},{n:'Sub sub category 3',u:7,s:[]}]}],items:['sku','sku2']},
        {n:'Category',u:2,p:'http://#',s:[{n:'Sub category',u:8,s:[{n:'Sub sub category',u:9,s:[],items:['sku','sku2']},{n:'Sub sub category 2',u:10,s:[],items:['sku','sku2']},{n:'Sub sub category 3',u:11,s:[],items:['sku','sku2']}],items:['sku','sku2']}],items:['sku','sku2']},
        {n:'Category',u:3,p:'http://#',s:[{n:'Sub category',u:12,s:[{n:'Sub sub category',u:13,s:[],items:['sku','sku2']},{n:'Sub sub category 2',u:14,s:[],items:['sku','sku2']},{n:'Sub sub category 3',u:15,s:[],items:['sku','sku2']}],items:['sku','sku2']}],items:['sku','sku2']}
    ]

Recursive solution:

function searchRecursive(needle, haystack) {
  for (var i=0; i<haystack.length; i++) {
    if (haystack[i].u === needle) return haystack[i];
    var search = searchRecursive(needle, haystack[i].s);
    if (search) return search;
  }
  return null;
}

// Usage:
searchRecursive(10, Categories) // Object {n: "Sub sub category 2", u: 10, s: Array[0], items: Array[2]}

Non-recursive solution:

function search(needle, haystack) {
  var queue = haystack.slice();

  while (queue.length) {
    var current = queue.shift();
    if (current.u === needle) return current;
    queue = queue.concat(current.s);
  }
  return null;
}

// Usage:
search(10, Categories) // Object {n: "Sub sub category 2", u: 10, s: Array[0], items: Array[2]}

Answer 2

You have not Array of Objects , you have Object of Objects . You may need to change:

var Categories = {

to:

var Categories = [

Then you will need to iterate over your Array recursivelly:

function getU( obj, u ) {
    var result = null;
    for (var i = 0, len = obj.length; i < len; i++) {
        if (obj[i].u === u) {
            result = obj[i];
            break;
        }
    }
    if( result === null ) {
        result = getU( obj[ i ].s, u)
    }
    return result;
}

and First time calling it like:

getU( Categories, u);

Where u is your ID you want to find.

Answer 3

Now that you have a better format (more normalized data) your search becomes a lot easier:

function getU(obj, u){
    for (var i = 0, r; i < obj.length && !r; i++){
        if (obj[i].u == u) return obj[i];
        r = getU(obj[i].s, u);
    }
    return r;
}

So, for example :

getU(Categories, 6)
// returns: {"n":"Sub sub category 2","u":6,"s":[],"items":["sku","sku2"]}
getU(Categories, 14)
// returns: {"n":"Sub sub category 2","u":14,"s":[],"items":["sku","sku2"]}

// and of course (upper-most node)
getU(Categories, 1)
// returns {"n":"Category","u":1,"p":"http://#","s":[{"n":"Sub category","u":4,"s":[{"n":"Sub sub category","u":5,"s":[],"items":["sku","sku2"]},{"n":"Sub sub category 2","u":6,"s":[],"items":["sku","sku2"]},{"n":"Sub sub category 3","u":7,"s":[],"items":["sku","sku2"]}],"items":["sku","sku2"]},{"n":"Sub category","u":4,"s":[{"n":"Sub sub category","u":5,"s":[]},{"n":"Sub sub category 2","u":6,"s":[]},{"n":"Sub sub category 3","u":7,"s":[]}]},{"n":"Sub category","u":4,"s":[{"n":"Sub sub category","u":5,"s":[]},{"n":"Sub sub category 2","u":6,"s":[]},{"n":"Sub sub category 3","u":7,"s":[]}]}],"items":["sku","sku2"]}