Convert multiple arrays to single JSON

Question

I need help converting several arrays:

x = ['a', 'b', 'c']
y = ['d', 'e', 'f']
z = ['d', 'g', 'h']

Into a single JSON:

{
    a: { b: { c: 'done' }},
    d: { e: { f: 'done' },
         g: { h: 'done' }}
}

Is this possible using recursion? I can't seem to get it working properly so I was wondering if there is already an easy way to do this in JS.

Answer 1

var struct = {};
var paths = [
    ['a', 'b', 'c'],
    ['d', 'e', 'f'],
    ['d', 'g', 'h']
];

paths.forEach(function (path) {
    var ref;
    ref = struct;
    path.forEach(function (elem, index) {
        if (!ref[elem]) {
            ref[elem] = index === path.length - 1 ? "done": {};
        }
        ref = ref[elem];
    });
});
console.log(JSON.stringify(struct, null, "\t"));

Output:

{
    "a": {
        "b": {
            "c": "done"
        }
    },
    "d": {
        "e": {
            "f": "done"
        },
        "g": {
            "h": "done"
        }
    }
}

Note: this script will fail if your input is like:

var paths = [
    ['a', 'b', 'c'],
    ['a', 'b', 'c', 'd' ]
];

It decided c should be "done" but then there is another level. maybe this wont ever happen, if it does, figure out what you want the result to be.

Answer 2

A version with Array#forEach() and Array#reduce()

 var x = ['a', 'b', 'c'], y = ['d', 'e', 'f'], z = ['d', 'g', 'h'], object = function (array) { var o = {}; array.forEach(function (a) { var last = a.pop(); a.reduce(function (r, b) { r[b] = r[b] || {}; return r[b]; }, o)[last] = 'done'; }); return o; }([x, y, z]); document.write('<pre>' + JSON.stringify(object, 0, 4) + '</pre>');