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			117 lines
		
	
	
		
			3.9 KiB
		
	
	
	
		
			Markdown
		
	
	
	
	
	
| ---
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| id: 56533eb9ac21ba0edf2244e0
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| title: Replacing If Else Chains with Switch
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| challengeType: 1
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| videoUrl: 'https://scrimba.com/c/c3JE8fy'
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| ---
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| 
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| ## Description
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| <section id='description'>
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| If you have many options to choose from, a <code>switch</code> statement can be easier to write than many chained <code>if</code>/<code>else if</code> statements. The following:
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| <blockquote>if (val === 1) {<br>  answer = "a";<br>} else if (val === 2) {<br>  answer = "b";<br>} else {<br>  answer = "c";<br>}</blockquote>
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| can be replaced with:
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| <blockquote>switch(val) {<br>  case 1:<br>    answer = "a";<br>    break;<br>  case 2:<br>    answer = "b";<br>    break;<br>  default:<br>    answer = "c";<br>}</blockquote>
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| </section>
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| 
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| ## Instructions
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| <section id='instructions'>
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| Change the chained <code>if</code>/<code>else if</code> statements into a <code>switch</code> statement.
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| </section>
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| 
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| ## Tests
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| <section id='tests'>
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| 
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| ```yml
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| tests:
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|   - text: You should not use any <code>else</code> statements anywhere in the editor
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|     testString: assert(!/else/g.test(code), 'You should not use any <code>else</code> statements anywhere in the editor');
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|   - text: You should not use any <code>if</code> statements anywhere in the editor
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|     testString: assert(!/if/g.test(code), 'You should not use any <code>if</code> statements anywhere in the editor');
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|   - text: You should have at least four <code>break</code> statements
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|     testString: assert(code.match(/break/g).length >= 4, 'You should have at least four <code>break</code> statements');
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|   - text: <code>chainToSwitch("bob")</code> should be "Marley"
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|     testString: assert(chainToSwitch("bob") === "Marley", '<code>chainToSwitch("bob")</code> should be "Marley"');
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|   - text: <code>chainToSwitch(42)</code> should be "The Answer"
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|     testString: assert(chainToSwitch(42) === "The Answer", '<code>chainToSwitch(42)</code> should be "The Answer"');
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|   - text: "<code>chainToSwitch(1)</code> should be \"There is no #1\""
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|     testString: "assert(chainToSwitch(1) === \"There is no #1\", '<code>chainToSwitch(1)</code> should be \"There is no #1\"');"
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|   - text: <code>chainToSwitch(99)</code> should be "Missed me by this much!"
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|     testString: assert(chainToSwitch(99) === "Missed me by this much!", '<code>chainToSwitch(99)</code> should be "Missed me by this much!"');
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|   - text: <code>chainToSwitch(7)</code> should be "Ate Nine"
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|     testString: assert(chainToSwitch(7) === "Ate Nine", '<code>chainToSwitch(7)</code> should be "Ate Nine"');
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|   - text: <code>chainToSwitch("John")</code> should be "" (empty string)
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|     testString: assert(chainToSwitch("John") === "", '<code>chainToSwitch("John")</code> should be "" (empty string)');
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|   - text: <code>chainToSwitch(156)</code> should be "" (empty string)
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|     testString: assert(chainToSwitch(156) === "", '<code>chainToSwitch(156)</code> should be "" (empty string)');
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| 
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| ```
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| 
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| </section>
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| 
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| ## Challenge Seed
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| <section id='challengeSeed'>
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| 
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| <div id='js-seed'>
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| 
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| ```js
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| function chainToSwitch(val) {
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|   var answer = "";
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|   // Only change code below this line
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| 
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|   if (val === "bob") {
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|     answer = "Marley";
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|   } else if (val === 42) {
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|     answer = "The Answer";
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|   } else if (val === 1) {
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|     answer = "There is no #1";
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|   } else if (val === 99) {
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|     answer = "Missed me by this much!";
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|   } else if (val === 7) {
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|     answer = "Ate Nine";
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|   }
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| 
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|   // Only change code above this line
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|   return answer;
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| }
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| 
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| // Change this value to test
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| chainToSwitch(7);
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| 
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| ```
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| 
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| </div>
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| 
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| 
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| 
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| </section>
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| 
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| ## Solution
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| <section id='solution'>
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| 
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| 
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| ```js
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| function chainToSwitch(val) {
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|   var answer = "";
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| 
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|   switch(val) {
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|     case "bob":
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|       answer = "Marley";
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|       break;
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|     case 42:
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|       answer = "The Answer";
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|       break;
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|     case 1:
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|       answer = "There is no #1";
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|       break;
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|     case 99:
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|       answer = "Missed me by this much!";
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|       break;
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|     case 7:
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|       answer = "Ate Nine";
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|   }
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|   return answer;
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| }
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| ```
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| 
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| </section>
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