Some possible options

• Tabs vs spaces
  • Number of spaces
• Space after commas
• Space b/w keyword and open paren (ex: for (...)
• Braces same line vs next
• Semicolons
• Single vs double quotes

for (var i = 1; i <= 100; ++i) {
    if (i % 15 === 0) {
        console.log('FizzBuzz');
    } else if (i % 3 === 0) {
        console.log('Fizz');
    } else if (i % 5 === 0) {
        console.log('Buzz');
    } else {
        console.log(i);
    }
}

(from escodegen online demo) ends up increasingly nesting successive ifs

There are so many of them!