Strings look simple... until they surprise you.

Short summary

A beginner-friendly tutorial explaining how strings work behind the scenes in JavaScript, covering immutability, performance implications of repeated string concatenation, and why methods like toUpperCase() return new strings rather than modifying originals. Uses simple analogies (printed books) to explain why immutability prevents bugs. Touches on performance pitfalls when building large strings in loops and suggests using array join patterns instead.

• •Strings in JavaScript are immutable—methods return new strings, never modify the original
• •Repeated string concatenation in loops creates many temporary strings, hurting performance
• •Use array.push + join instead of += for building large text from many pieces

Generated with AI, which can make mistakes.