Check if object member exists in nested object

Question

Is there a simpler way than using ___ in object to check the existence of each level of an object to check the existence of a single member?

More conci

Answer 1

If you can use lodash library, it has a very elegant solution, hasIn.

_.hasIn(someObject, 'member.level1.level2.level3');

for example,

var obj = {'x': 999, 'a': {'b': {'c': 123, 'd': 234}}}
// => undefined

_.hasIn(obj, 'x')
// => true

_.hasIn(obj, 'a.b.d')
// => true

_.hasIn(obj, 'a.b.e')
// => false

Answer 2

In general, you can use if(property in object), but this would be still cumbersome for nested members.

You could write a function:

function test(obj, prop) {
    var parts = prop.split('.');
    for(var i = 0, l = parts.length; i < l; i++) {
        var part = parts[i];
        if(obj !== null && typeof obj === "object" && part in obj) {
            obj = obj[part];
        }
        else {
            return false;
        }
    }
    return true;
}

test(someObject, 'member.member.member.value');

DEMO