data types
-
string
-
number
-
boolean
-
null // absence of value
-
undefined // not yet assigned a value
-
bigint // greater range of number
-
symbol // unique identifier
-
Operator
let timeRemaining = 0
let energy = 10
console.log(`Game over: ${timeRemaining == 0 || energy == 0}`)
- boolean
true
false
- typeof
typeof var
- convert string to integer
parseInt(var)
- unary operator
+ prompt(' ')
- convert string to float
parseFloat(var)
- String Interpolation
console.log(`Hello ${firstName} ${lastName}`)
- Arrow Function Syntax
const lineBreak = () => console.log("");
-
Debugging
-
object
var king = { firstName: "Ned", lastName:"Stark", age:40};
Object.keys(king);
["firstName", "lastName", "age"]
- if
if(condition){
}
- for
for(initiation; condition; update){
}
- array
array.length
array.push(var) // add element to the last
- math
const secsPerMin = 60;
const minsPerHour = 60;
const hoursPerDay = 24;
const daysPerWeek = 7;
const weeksPerYear = 52;
const secondsPerDay = hoursPerDay * minsPerHour * secsPerMin;
let sentence = document.querySelector('main')
sentence.innerHTML = `<h1>There are ${secondsPerDay} seconds in a day.</h1>`;
const yearsAlive = 34 * weeksPerYear * daysPerWeek * hoursPerDay * minsPerHour * secsPerMin;
sentence.innerHTML += `<h2>I've been alive for more than ${yearsAlive} seconds!</h2>`;