Merge pull request learn-co-students#1 from kthffmn/master

add if/if else/if else if else/ternary/switch info

Author: kthffmn

.learn

@@ -0,0 +1,9 @@
+tags:
+  - control flow
+  - ternary operator
+  - if statements
+  - if/else statements
+  - if/else if/else statements
+languages:
+  - javascript
+resources: 4

LICENSE.md

@@ -1 +1,202 @@
-# intro-to-flow-control.js
+# JavaScript Flow Control
+
+## Overview
+
+* About
+* If Statements
+* If/Else Statements
+* If/Else if/Else Statements
+* Ternary Operators
+* Switch Statments
+* Resources
+
+## About
+
+Flow Control allows the excution of code only under certain conditions. In Ruby, we used case statments, if statments, if/else statements, if/elsif/else statements, ternary operators, and case statements to control what code runs when. JavaScript has similar methods to control what blocks of code to execute: if statements, if/else statements, if/else if/else statements, ternary operators, and switch statements.
+
+## If Statements
+
+Evaluates the code wrapped in parenthesis to either true or false. If `true`, the code block is executed: 
+
+Syntax:
+
+```javascript
+if (conditionToTestIsTrue) {
+  // code to be executed here
+}
+```
+
+Example:
+
+```javascript
+var num = 7;
+
+if (num < 10) {
+  console.log(num + " is less than ten");
+}
+
+// This will print "7 is less than ten" to the console
+```
+
+## If/Else Statements
+
+You will often see an `If` statement used in combination with an  `else` clause. An `else` clause is a fallback to an `if` statement and will only get executed if the previous `if` statement is false.
+    
+Syntax:
+
+```javascript
+if (conditionToTestIsTrue) {
+  // codition is false hence code is not executed
+} else {
+  // code to be executed because previous `if` condition is false
+}
+```
+
+Example:
+
+```javascript
+var num = 11;
+
+if (num < 10) {
+  console.log(num + " is less than ten");
+} else {
+  console.log(num + " is more than or equal to ten");
+}
+
+// This will print "11 is more than or equal to ten" to the console
+```
+
+## If/Else if/Else Statements
+
+`if` statements can also be combined with an `else if` clause. This is like an else statement, but with its own condition. It will only run if its condition is true, and the previous statement's condition was false. 
+
+Note: An important thing to keep in mind when transitioning to JavaScript from Ruby is that the `elsif` becomes two full words: `else if`.
+
+Syntax:
+
+```javascript
+if (conditionToTestIsTrue){
+    // codition is false hence code is not executed
+} else if (thisCondionIsTrue) {
+  // excute this code if previous `if` statement is false
+} else {
+  // excute this code if the 2 conditions above are false
+}
+```
+
+Example:
+
+```javascript
+var num = 10;
+
+if (num < 10) {
+  console.log(num + " is less than ten");
+} else if (num == 10) {
+  console.log(num + " is equal to ten");
+} else {
+  console.log(num + " is more than ten");
+}
+
+// This will print "10 is equal to ten" to the console
+```
+
+## Ternary Operator
+
+The ternary operator is used as a shortcut for the `if-else` statement. You've probably seen it before in Ruby looking something like this:
+
+```ruby
+cart = ["graphic t-shirt", "aluminum water bottle"]
+
+puts cart.empty? ? "Please add something to your cart." : "You're ready to check out." 
+
+# Above prints:
+# You're ready to check out.
+```
+
+This operator tests a condition; if the condition is true, it returns a certain value, otherwise it returns a different value:
+
+Syntax:
+
+```javascript
+conditionToTest ? valueToBeReturnedIfTrue : valueToBeReturnedIfFalse
+```
+
+Example:
+
+```javascript
+var num = 7;
+num > 10 ? console.log(num + " is bigger than 10") : console.log(num + " is not bigger than 10");
+// this will print "7 is not bigger than 10"
+```
+
+## Switch Statements
+
+Switch statements acts like a big if/else if/else chain. The switch expression is evaluated once and the value of the expression is compared with the values of each case. If there is a match, the associated block of code is executed.
+
+Syntax:
+
+```javascript
+switch (expression) {
+  case n:
+      // code to be executed if case n is true
+      break; // break out of switch statement once code executed
+  case m:
+      // code to be executed if case m is true
+      break; // break out of switch statement once code executed
+  default:  // all other cases
+      // code to be executed if case n and case m false
+}
+```
+  
+First Example:
+
+```javascript
+var diet = "vegetarian";
+
+switch (diet) {
+  case "vegetarian":
+    console.log("Where do you get your protein? :P ");
+  case "gluten free":
+    console.log("Wow, that eliminates all the best foods! :( ");
+  default:
+    console.log("Sounds like you're an omnivore.");
+}
+
+// Output:
+// Where do you get your protein? :P 
+// Wow, that eliminates all the best foods! :( 
+// Sounds like you're an omnivore.
+
+// Why????
+// Because no breaking statement is found it executes all of the cases after the true case (which is case 1)
+```
+
+Second Example:
+
+```javascript
+var diet = "vegetarian";
+
+switch (diet) {
+  case "vegetarian":
+    console.log("Where do you get your protein? :P ");
+  case "gluten free":
+    console.log("Wow, that eliminates all the best foods! :( ");
+    break;
+  default:
+    console.log("Sounds like you're an omnivore.");
+}
+
+// Output:
+// Where do you get your protein? :P 
+// Wow, that eliminates all the best foods! :( 
+
+// Why????
+// Because break statement is found at the second case so execution stops there
+```
+
+## Resources
+
+* [Codecademy - if/if else/if else if else](http://www.codecademy.com/glossary/javascript/if-statement)
+* [MDN - if..else](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Statements/if...else)
+* [Codecademy - Ternary Operator](http://www.codecademy.com/glossary/javascript/ternary-operator)
+* [Codecademy - Switch Statements](http://www.codecademy.com/glossary/javascript/switch-statements)