Accessing Nested JavaScript Objects and Arrays by String Path
Accessing deeply nested objects and arrays in JavaScript can be a cumbersome task. To simplify this, a solution has emerged that leverages a string path to directly retrieve specific values.
Pure JavaScript Solution
A pure JavaScript solution called "Object.byString()" enables the extraction of nested values using a string that follows a dot-separated path. This solution functions as follows:
Object.byString = function(o, s) { s = s.replace(/\[(\w+)\]/g, '.'); // 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');
jQuery Solution
jQuery offers a simpler syntax for accessing nested values:
$('someObj').data('part3[0].name');
Example Usage
Consider the following object:
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' } ] };
Using the provided string paths, we can access specific values as follows:
var part1name = Object.byString(someObject, 'part1.name'); var part2quantity = Object.byString(someObject, 'part2.qty'); var part3name1 = Object.byString(someObject, 'part3[0].name');
These variables will now hold the corresponding values from the nested object.
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