Block Scope

Variables declared with block scope:

• Are declared using let and const
• Are usable in the block where they're declared
• A block is anywhere encompassed with {}
• Cause a ReferenceError if used before declaration

Block scope is my personal preference. This way I can't accidentally use variables before they've been declared, and it is one less place that I can have a bug in my code.

For more information on this topic, check out this blog post.