I'm new to JavaScript and learning it for a week now. I had applied for an internship in different companies and I was called yesterday for an interview. They asked me some questions and for this one particular question, I had no clue. Can someone provide me the solution or help me clarify this proxy topic.
What is the solution to this Question?
Please write a simple log function that will proxy a string argument to console.log() *
If I were asked this question I would understand "that will proxy a string" to mean "that will pass on a string ... in a controlled way". Wikipedia writes about the Proxy pattern:
What problems can the Proxy design pattern solve?
- The access to an object should be controlled.
- Additional functionality should be provided when accessing an object.
So in this case you would verify that the argument is a string, or another interpretation could be that you would convert a non-string to string before passing it on to console.log. So I think the following two answers would be OK:
function log(str) {
if (typeof str !== "string") throw new TypeError("log should not be called with a non-string");
console.log(str);
}
log("hello");Or:
function log(str) {
if (typeof str !== "string") str = JSON.stringify(str);
console.log(str);
}
log(["an", "array"]);**
function log(){
console.log(...arguments);
}
log("a", "b")**
Proxyis basically a something that intercepts an interaction with an underlying function or property and adds some extra logic to the underlying function or property before invoking/changing/returning that value to the caller. This question is quite ambiguous and more explanation is required for a better answer. You should have asked follow up questions regarding this.