JavaScript - get nested property value by path (resistant to null/undefined)

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
// custom function solution when property names don't contain '.'

function getValue(object, path) {
    return path.split('.')
               .reduce(function(value, key) {
                   return value == null ? value : value[key];
               }, object);
}


// Usage example:

var myObject = {
    name: 'John',
    metadata: {
        type: 'json',
    },
};

var metadata = getValue(myObject, 'metadata');
var type = getValue(myObject, 'metadata.type');

console.log(metadata); // { type: 'json' }
console.log(type);     // json