Accessing nested JavaScript objects and arrays by string path

javascript, nested, path

Solution

I just made this based on some similar code I already had, it appears to work:

Object.byString = function(o, s) {
    s = s.replace(/\[(\w+)\]/g, '.$1'); // convert indexes to properties
    s = s.replace(/^\./, '');           // strip a leading dot
    var a = s.split('.');
    for (var i = 0, n = a.length; i < n; ++i) {
        var k = a[i];
        if (k in o) {
            o = o[k];
        } else {
            return;
        }
    }
    return o;
}

Usage::

Object.byString(someObj, 'part3[0].name');

See a working demo at http://jsfiddle.net/alnitak/hEsys/

EDIT some have noticed that this code will throw an error if passed a string where the left-most indexes don't correspond to a correctly nested entry within the object. This is a valid concern, but IMHO best addressed with a `try / catch` block when calling, rather than having this function silently return `undefined` for an invalid index.

Problem

I have a data structure like this : ``` var someObject = { 'part1' : { 'name': 'Part 1', 'size': '20', 'qty' : '50' }, 'part2' : { 'name': 'Part 2', 'size': '15', 'qty' : '60' }, 'part3' : [ { 'name': 'Part 3A', 'size': '10', 'qty' : '20' }, { 'name': 'Part 3B', 'size': '5', 'qty' : '20' }, { 'name': 'Part 3C', 'size': '7.5', 'qty' : '20' } ] }; ``` And I would like to access the data using these variable : ``` var part1name = "part1.name"; var part2quantity = "part2.qty"; var part3name1 = "part3[0].name"; ``` part1name should be filled with `someObject.part1.name` 's value, which is "Part 1". Same thing with part2quantity which filled with 60. Is there anyway to achieve this with either pure javascript or JQuery?

Original source

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