Introduction to JavaScript

day1.md

Let's Get Crunk!

@ Netscape in 1995 to parody VB

Codename called Mocha, later LiveScript in Navigator 2.0 Beta

Numbers

• Everything You Never Wanted To Know About JavaScript Numbers
• object like (has methods)
• immutable (by value)
• type detection: typeof value === 'number' && isFinite(value)
• creation
  • 0
  • 0.0
• typecast
  • Number(value)
  • +value
  • parseFloat(value, 10)
  • parseInt(value, 10)
• useful methods
  • .toString()
  • .toFixed(units)
  • .toPrecision(digits)
• gotcha!
  • typeof NaN === 'number'
  • typeof Infinity === 'number'

Strings

• object like (has methods)
• immutable (by value)
• type detection: typeof value === 'string'
• creation
  • "value"
  • 'value'
  • String(value)
• typecast
  • String(value)
  • value + ''
  • value.toString() (where available)
• useful methods
  • .charAt(index)
  • .fromCharCode(asciiCode)
  • .indexOf(character)
  • .toUpperCase()
  • .toLowerCase()
  • .substr(start, length)
  • .substring(start, end)
  • .split(char)

Booleans

• object like (has methods)
• immutable (by value)
• creation
  • true
  • false
• typecast
  • !!value
• useful methods
  • .toString()

undefined

• on the global :(
• can be overwritten :(
• type detection: typeof value === 'undefined'

null

• a literal \o/!
• used to clear out a variables value (don't use undefined)
• type detection: value === null

Objects

• mutable (by reference)
• keyed collections

Object

• type detection: obj && typeof obj === 'object'
• look up: obj.key obj['key']
• creation
  • { }
• useful methods
  • .hasOwnProperty(value)
  • .__proto__ (inheritance?)
• JSON
  • JSON.stringify(obj)
  • JSON.parse(str)

Array

• type detection: Object.prototype.toString.call(arr) === '[object Array]'
• look up: arr[index]
• creation
  • [ ]
• useful methods
  • .sort()
  • .indexOf()
  • .push()
  • .pop()
  • .shift()
  • .unshift()
  • .slice(start[, end])
  • .splice(index, howManyToRemove[, nItemsToAdd])

Function

• type detection: typeof fn === 'function'
• hoisted
• creation
  • function () {}
  • funciton Name () {}
• useful methods
  • .apply()
  • .call()

Regular Expressions

• type detection: Object.prototype.toString.call(reg) === '[object RegExp]'
• creation
  • /./
  • new RegExp('.')
• useful methods
  • .test(str)
  • .exec(str)