Getting Started with JS, v2 by Kyle Simpson [Programming Primer]

Getting Started with JavaScript, v2 by Kyle Simpson

Course Materials

Programming Primer Notes

Operations

• JavaScript operators are symbols that are used to perform operations on operands.

Types

• typeof operator is used to return a string that represents the type of JavaScript for a given value.

console.log(typeof 42)
// Expected output: "number"

console.log(typeof 'blubber')
// Expected output: "string"

console.log(typeof true)
// Expected output: "boolean"

Variables

• A variable is a named reference to a value (Representation of some place in memory).

Expresions and Statements

• Part of a statement is an expression.

If & Else (Decisions)

if (condition) statement1

// With an else clause
if (condition) statement1
else statement2

Loops

• The statements for loops provided in JavaScript are:

1. for statement
2. do...while statement
3. while statement
4. labeled statement
5. break statement
6. continue statement
7. for...in statement
8. for...of statement

for (initialization; condition; afterthought) statement

//

for (let step = 0; step < 5; step++) {
  // Runs 5 times, with values of step 0 through 4.
  console.log('Walking east one step')
}

Functions

• functions are first-class objects, because they can be passed to other functions, returned from functions, and assigned to variables and properties.
• They can also have properties and methods just like any other object. - What distinguishes them from other objects is that functions can be called.

function square(number) {
  return number * number
}

function expression

• The function keyword can be used to define a function inside an expression.
• The main difference between a function expression and a function declaration is the function name, which can be omitted in function expressions to create anonymous functions.

const getRectArea = function (width, height) {
  return width * height
}

console.log(getRectArea(3, 4))
// Expected output: 12