JavaScript Performance For Madmen

JavaScript performance is terrifying and unpredictable. If you want things to run fast, you'll need a dowsing rod, but these test cases might help:

• Object.defineProperty versus regular property assignment
• Performance hit for initializing properties in different orders in your constructor (Hidden Classes)
• Deeply nested prototype chains
• String concatenation versus array.join
• Truncating numbers
• Object.create vs new