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' } ] }; I want to access the data using the following variables:
var part1name = "part1.name"; var part2quantity = "part2.qty"; var part3name1 = "part3[0].name";
part1name should be filled with the value of someObject.part1.name, which is "Part 1". The same goes for part2quantity, which is padded to 60.
Is there a way to achieve this using pure JavaScript or JQuery?
![[Web front-end] Node.js quick start](https://img.php.cn/upload/course/000/000/067/662b5d34ba7c0227.png)
This is now supported via lodash using
_.get(obj, property). Seehttps://lodash.com/docs#getExample from documentation:
var object = { 'a': [{ 'b': { 'c': 3 } }] }; _.get(object, 'a[0].b.c'); // → 3 _.get(object, ['a', '0', 'b', 'c']); // → 3 _.get(object, 'a.b.c', 'default'); // → 'default'I just created this based on some similar code I already had and it seems to work:
Object.byString = function(o, s) { s = s.replace(/\[(\w+)\]/g, '.'); // 将索引转换为属性 s = s.replace(/^\./, ''); // 去掉前导点 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:
View a working example athttp://jsfiddle.net/alnitak/hEsys/.
EDITSome people have noticed that this code will throw an error if passed a string where the leftmost index does not correspond to a properly nested entry in the object. This is a valid concern, but I think it's better handled using a
try/catchblock when called, rather than having this function silently returnundefined.