TypeError: str.toLowerCase is not a function

[waitingcheung]

I am trying to detect a phone number as a Number and it seems that Knwl.js accepts only strings and the following TypeError occurs.

TypeError: str.toLowerCase is not a function
    at Knwl.init (/path/knwl.js:1154:23)

Here is a test case that reproduces the problem.

var knwl = new Knwl();
var phone = 5555555555;
knwl.init(phone);
console.log(knwl.get('phones'));

To fix the problem, we may change line 1154 to the following

var lowercase = String(str).toLowerCase();