Semicolons: Always use.
Naming: Use camel case everywhere but constants. Use all caps snake case for constants.
Strings: Use single quotes.
Curly Braces: Start your curly braces on the same line as whatever they're opening.
Spacing: Indent new lines two spaces. Put a space between arguments in a function. For parentheses/curly brackets, no spaces after opening bracket and before closing.
If you're unsure about a particular situation during the assessment, refer to the Google JS Style Guide at https://google.github.io/styleguide/jsguide.html.