varvslet- What are closures? (one sentence)
- What are the differences between a promise and an observable?
- What is a potential pitfall with using typeof bar === "object" to determine if bar is an object? How can this pitfall be avoided?
- What is the significance, and what are the benefits, of including 'use strict' at the beginning of a JavaScript source file?
- What is NaN? What is its type? How can you reliably test if a value is equal to NaN?