JavaScript Foundations

What you'll learn

• What actually runs your JavaScript and where
• How primitive values differ from objects in memory and behaviour
• How let, const, and var scope themselves to blocks or functions
• Why == surprises people and why === ends the surprise
• How to steer code with if, switch, and the loop family
• How to throw, catch, and choose when to let an error fly

1. 01
   What JavaScript actually is

   Engines, runtimes, and the spec your code conforms to.
   13 min
2. 02
   Values and types

   The seven primitives, the object kingdom, and what typeof tells you.
   18 min
3. 03
   Variables

   let, const, and var — block scope, function scope, and the temporal dead zone.
   18 min
4. 04
   Operators and expressions

   Arithmetic, logic, short-circuits, and the ternary you actually want.
   18 min
5. 05
   Equality and coercion

   Why == surprises people, the truthy table, and the rule that ends the pain.
   20 min
6. 06
   Control flow

   if, switch, the loop family, and the gotcha that bites every newcomer.
   18 min
7. 07
   Strings and numbers, briefly

   Template literals, common methods, and why 0.1 + 0.2 isn't 0.3.
   19 min
8. 08
   Errors

   throw, try/catch/finally, built-in error types, and when to let it fly.
   16 min