Loops.js

/*
 * Loops
 *
 */


/*
  Many types of loops but all do basically the same thing:
  repeat something (i.e. an action) a set number of times (could
  even be 0).
*/


// While loop
/*
  while(condition) {
    statement
  }
*/



let numberOfLoops = 0;
while(numberOfLoops < 10) {
  console.log("I am looping!");
  numberOfLoops += 1;
}


let num1 = 0;
let num2 = 0;
while (num1 < 100) {
  num1 += 1;
  num2 += num1;

}
console.log(num2);

const names = ["Chris", "Bob", "Joe", "Jane", "Amy", "Ashley", "Billy"];


function nameLooper(arr, userName) {
  let index = 0;
  while(index < arr.length){
    if (arr[index] === userName) {
      console.log(arr[index]);
      break;
    }
    index += 1;
  }
}



// do...while statement
/*
  do {
    statement
  } while(condition)
*/


let condition = false;

do {
  const userInput = prompt("Enter q to exit");
  if (userInput === 'q') {
    condition = false;
  } else {
    condition = true;
  }
} while(condition);

let totalMoney = 100;

do {
  checkIfCanPurchase();
} while(totalMoney > 500);

function checkIfCanPurchase() {
  if (totalMoney > 500) {
    console.log("Can purchase :)");
  } else {
    console.log("Cannot purchase :(");
  }
}

// For loops
// Repeat until a specified conditions evaluates to false
/*
  for(initial expression ; condition ; increment expression) {
    statement
  }
*/

const iceCreams = ["vanilla", "chocolate", "rocky road", "strawberry"];

function iceCreamLooper(arr, type) {
  for(var i = 0 ; i < arr.length ; i += 1) {
    if (arr[i] === type) {
      console.log(arr[i] + " " + "is at position: " + i);
    }
  }
}



for(let i = 1 ; i <= 100 ; i += 1 ) {
  if (i % 15 === 0) {
    console.log("Fizzbuzz");
  }
  else if (i % 3 === 0) {
    console.log("Fizz");
  }
  else if (i % 5 === 0) {
    console.log("Buzz");
  }
  else {
    console.log(i);
  }
}

console.log("Starting loop!");
outerLoop:
for(let i = 0 ; i < 10 ; i += 1) {
  console.log("Loop #" + i);
  innerLoop:
  for (let a = 0 ; a < 10 ; a += 1) {
    console.log("Inner loop #" + a);
    if (a === 3) {
      break innerLoop;
    }
    if (i === 5) {
      break outerLoop;
    }
  }
}
console.log("Finished loop");


for(let i = 0 ; i < 10 ; i += 1) {
  setTimeout(() => {
    console.log(i);
  }, i * 500);
}

// For...in loop
/*
  Loop through an object's properties in arbitrary order
  Used for looping over object properties
*/

const users = { a: "Sally", b: "Billy", g: "Ashley", x: "Timmy" };

for(let prop in users) {
  if (users[prop] === "Sally") {
    users[prop] = "Unknown";
  }
  console.log(users[prop]);
}


const drinks = ["coffee", "sprite", "tea", "coke", "pepsi"];

drinks.forEach((d) => {
  console.log(d);
});


//For...of loop
/*
  New loop in ES6 used to loop over iterable objects(arrays, strings,
  maps, sets, etc)
  For looping for data - like values in an array
*/

const drinks = ["coffee", "sprite", "tea", "coke", "pepsi"];
for(const d of drinks) {
  if (d === "tea") {
    continue;
  }
  console.log(d);
}

const myString = "🤖😓";
for(const character of myString) {
  console.log(character);
}

const originalArray = [10, 15, 20, 25, 30];

function numIncreaser(arr, numToIncBy) {
  for(let num of arr){
    num += numToIncBy;
    console.log(num);
  }
}

numIncreaser(originalArray, 30);

const originalArray = ["Chris", "Chris", "Jane", "Sally", "Billy", "Billy", "Bob"];
const uniqueNameSet = new Set(originalArray);

for(const n of uniqueNameSet) {
  console.log(n);
}