Getting Started with JS, v2 by Kyle Simpson [Types & Coercion]

Getting Started with JavaScript, v2 by Kyle Simpson

Course Materials

Types & Coercion Notes

Converting Types

• The way to convert from one type to another is coercion.

Falsy and Truthy

1. Falsy

- “”
- 0, -0
- null
- NaN
- false
- undefined

2. Truthy

- “foo”
- 23
- { a:1 }
- [1,3]
- true
- function()
- ...

Equality == vs ===

• == allows coercion (types different)

• === disallows coercion (types same)

Scope

• Scope: where to look for things.

• Undefined vs Undeclared - Undefined is a variable that has been declared, but it doesn't have a value. A variable thats never been declared is undeclared.

Immediately Invoked Function Expressions [IIFE]

• wrap the function with a function making it a function expression. and it's called as a value.

Block Scoping

• This scope restricts the variable that is declared inside a specific block, from access by the outside of the block.

Closure

• Closure is when a function remember the variables outside of it, even if you pass that function elsewhere.

this

• this references the execution context for that call, determined by how the function was called.

this.fn