Recap – Operators & Control Structures

by Joshua McNeese

JavaScript

// Conditional Statements

// if...else

var x = 1,
    y = 5;

if (x == y) {
	// statements...
} else if (y > 7) {
	// statements...
} else {
	// statements...
}

// switch
switch (x) { // an expression

    case 1:
        //statements...
        break;

    default:
        //statemetns...
       
}

// Loop statements

for (var i=10; i>1; i--) {
 
    // support breaks and continue
    if (i == 2) {
        continue;
    } else if (i == 9) {
        break;
    }
    
}

var x = 0;
while (x < 10) {
    x++;
}

var x = 0;
do {
    x++;
} while (x < 10);

// Enumerating over an object

var obj = {
    name: "Joshua",
    job: "Sleeping",
    favColors: ["Red", "Black", "Grey"]
}

for (var name in obj) {
    
    // only iterate properties that originate with obj
    if (obj.hasOwnProperty(name)) {
        
        console.log(obj[name]);
        
    }
    
}

// labels

loop1: for (var i = 0; i < 3; i++) {
   loop2: for (var j = 0; j < 3; j++) {
      if (i == 1 && j == 1) {
         continue loop1;
      }
      console.log("i = " + i + ", j = " + j);
   }
}