Add article about concatenate conditions

SamyPesse · SamyPesse · commit 216d03d7b771 · 2014-04-02T19:16:27.000-07:00
diff --git a/SUMMARY.md b/SUMMARY.md
@@ -15,4 +15,5 @@
 * [Conditional Logic](conditional/README.md)
     * [If](conditional/if.md)
     * [Else](conditional/else.md)
-    * [Comparators](conditional/comparators.md)
+    * [Comparators](conditional/comparators.md)
+    * [Concatenate](conditional/concatenate.md)
diff --git a/conditional/concatenate.md b/conditional/concatenate.md
@@ -0,0 +1,59 @@
+# Concatenate conditions
+
+Furthermore you can concatenate different conditions with "or” or “and” statements, to test whether either statement is true, or both are true, respectively.
+
+In JavaScript “or” is written as `||` and “and” is written as `&&`.
+
+Say you want to test if the value of x is between 10 and 20—you could do that with a condition stating:
+
+```
+if(x > 10 && x < 20) {
+    ...
+}
+```
+
+If you want to make sure that country is either “England” or “Germany” you use:
+
+```
+if(country === 'England' || country === 'Germany') {
+    ...
+}
+```
+
+**Note**: Just like operations on numbers, Condtions can be grouped using parenthesis, ex: ```if ( (name == "John" || name == "Jennifer") && country == "France")```.
+
+---
+
+Fill up the 2 conditions so that `primaryCategory` equals `"E/J"` only if name equals `"John"` and country is `"England"`, and so that `secondaryCategory` equals `"E|J"` only if name equals `"John"` or country is `"England"` 
+
+```js
+var name = "John";
+var country = "England";
+var primaryCategory, secondaryCategory;
+
+if ( /* Fill here */ ) {
+    primaryCategory = "E/J";
+}
+if ( /* Fill here */ ) {
+    secondaryCategory = "E|J";
+}
+```
+
+```js
+var name = "John";
+var country = "England";
+var primaryCategory, secondaryCategory;
+
+if (name == "John" && country == "England") {
+    primaryCategory = "E/J";
+}
+if (name == "John" || country == "England") {
+    secondaryCategory = "E|J";
+}
+```
+
+```js
+assert(primaryCategory == "E/J" && secondaryCategory == "E|J");
+```
+
+---
