62 lines
1.6 KiB
Markdown
62 lines
1.6 KiB
Markdown
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---
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title: Global Scope and Functions
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---
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## Global Scope and Functions
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<!-- The article goes here, in GitHub-flavored Markdown. Feel free to add YouTube videos, images, and CodePen/JSBin embeds -->
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The scope of a variable is its visibility; where in the code is the function available? Here is a list of the different scopes a variable can have.
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* **Global scope**: The variable is available throughout the code
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* **Local scope**: Available in only a certain area (like only within function)
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* **Block scope**: Available within an *even more* certain area (like an if-statement)
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Your task is to understand how adding `var` (and not adding) before a variable name, can change the variable's scope.
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When you add `var` before the variable name, its scope is determined by where it is placed. Like so:
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```javascript
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var num1 = 18; // Global scope
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function fun() {
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var num2 = 20; // Local (Function) Scope
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if (true) {
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var num3 = 22; // Block Scope (within an if-statement)
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}
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}
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```
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When you don't, this is the result:
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```javascript
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num1 = 18; // Global scope
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function fun() {
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num2 = 20; // Global Scope
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if (true) {
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num3 = 22; // Global Scope
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}
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}
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```
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Alright, here is the basic code solution.
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```javascript
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// Declare your variable here
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var myGlobal = 10;
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function fun1() {
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oopsGlobal = 5;
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}
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// Only change code above this line
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function fun2() {
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var output = "";
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if (typeof myGlobal != "undefined") {
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output += "myGlobal: " + myGlobal;
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}
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if (typeof oopsGlobal != "undefined") {
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output += " oopsGlobal: " + oopsGlobal;
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}
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console.log(output);
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}
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```
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