JavaScript safe access of deeply nested objects

safe.js

// https://medium.com/javascript-inside/safely-accessing-deeply-nested-values-in-javascript-99bf72a0855a#.wc89qfbqv

// get returns the element given by path p from object o, returning default d if not found
var get = function(p, o, d) {
        return p.reduce( function(xs, x) {
            return (xs && xs[x]) ? xs[x] : d;
        }, o);
    };

// usage:
var props = {
  user: {
    posts: [
      { title: 'Foo', comments: [ 'Good one!', 'Interesting...' ] },
      { title: 'Bar', comments: [ 'Ok' ] },
      { title: 'Baz', comments: [] },
    ]
  }
}

var comments = get(["user", "posts", 0, "comments"], props); // returns [ 'Good one!', 'Interesting...' ]
var empty = get(["user", "posts", 2, "comments"], props); // returns []
var def1 = get(["user", "posts", 2, "comments", 0], props); // returns undefined
var def2 = get(["user", "posts", 2, "comments", 0], props, "default"); // returns "default"


// alternate syntax
const get = (p, o, d) => p.reduce((xs, x) => (xs && xs[x]) ? xs[x] : d, o)