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Switch statement for multiple cases in JavaScript

Asked 12 years, 9 months ago

Viewed 1.3m times

I need multiple cases in switch statement in JavaScript, Something like:

switch (varName)
{
   case "afshin", "saeed", "larry":
       alert('Hey');
       break;

   default:
       alert('Default case');
       break;
}

How can I do that? If there's no way to do something like that in JavaScript, I want to know an alternative solution that also follows the DRY concept.

Archulan

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asked Nov 3, 2012 at 9:43

Afshin MehrabaniAfshin Mehrabani

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2

Use the fall-through feature of the switch statement. A matched case will run until a break (or the end of the switch statement) is found, so you could write it like:

switch (varName)
{
   case "afshin":
   case "saeed":
   case "larry": 
       alert('Hey');
       break;

   default: 
       alert('Default case');
}
user229044

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answered Nov 3, 2012 at 9:44

kennytmkennytm

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10

This works in regular JavaScript:

function theTest(val) {
  var answer = "";
  switch( val ) {
    case 1: case 2: case 3:
      answer = "Low";
      break;
    case 4: case 5: case 6:
      answer = "Mid";
      break;
    case 7: case 8: case 9:
      answer = "High";
      break;
    default:
      answer = "Massive or Tiny?";
  }
  return answer;
}

theTest(9);
Peter Mortensen

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answered Jan 17, 2016 at 2:15

Rob WelanRob Welan

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7

Here's different approach avoiding the switch statement altogether:

var cases = {
  afshin: function() { alert('hey'); },
  _default: function() { alert('default'); }
};
cases.larry = cases.saeed = cases.afshin;

cases[ varName ] ? cases[ varName ]() : cases._default();

answered Nov 3, 2012 at 9:55

elclanrselclanrs

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11

In Javascript to assign multiple cases in a switch, we have to define different case without break inbetween like given below:

   <script>
      function checkHere(varName){
        switch (varName)
           {
           case "saeed":
           case "larry":
           case "afshin":
                alert('Hey');
                break;
          case "ss":
               alert('ss');
               break;
         default:
               alert('Default case');
               break;
       }
      }
     </script>

Please see example click on link

Geo

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answered Nov 3, 2012 at 9:53

Er. Anurag JainEr. Anurag Jain

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1

I like this for clarity and a DRY syntax.

varName = "larry";

switch (true)
{
    case ["afshin", "saeed", "larry"].includes(varName) :
       alert('Hey');
       break;

    default:
       alert('Default case');

}
Peter Mortensen

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answered Feb 4, 2020 at 0:16

Kyle DudleyKyle Dudley

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3

If you're using ES6, you can do this:

if (['afshin', 'saeed', 'larry'].includes(varName)) {
   alert('Hey');
} else {
   alert('Default case');
}

Or for earlier versions of JavaScript, you can do this:

if (['afshin', 'saeed', 'larry'].indexOf(varName) !== -1) {
   alert('Hey');
} else {
   alert('Default case');
}

Note that includes won't work in some browser including older IE versions, but you could patch things up fairly easily. See the question determine if string is in list in javascript for more information.

answered Jul 30, 2013 at 20:11

ErikEErikE

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6

My situation was something akin to:

switch (text) {
  case SOME_CONSTANT || ANOTHER_CONSTANT:
    console.log('Case 1 entered');

  break;

  case THIRD_CONSTANT || FINAL_CONSTANT:
    console.log('Case 2 entered');

  break;

  default:
    console.log('Default entered');
}

The default case always entered. If you're running into a similar multi-case switch statement issue, you're looking for this:

switch (text) {
  case SOME_CONSTANT:
  case ANOTHER_CONSTANT:
    console.log('Case 1 entered');

  break;

  case THIRD_CONSTANT:
  case FINAL_CONSTANT:
    console.log('Case 2 entered');

  break;

  default:
    console.log('Default entered');
}
Peter Mortensen

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answered Jan 7, 2020 at 13:46

Mike KMike K

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Adding and clarifying Stefano's answer, you can use expressions to dynamically set the values for the conditions in switch, e.g.:

var i = 3
switch (i) {
    case ((i>=0 && i<=5) ? i : -1):
        console.log('0-5');
        break;

    case 6: console.log('6');
}

So in your problem, you could do something like:

var varName = "afshin"
switch (varName) {
    case (["afshin", "saeed", "larry"].indexOf(varName)+1 && varName):
      console.log("hey");
      break;

    default:
      console.log('Default case');
}

Although it is so much DRY...

Peter Mortensen

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answered Dec 6, 2017 at 15:10

Bernardo Dal CornoBernardo Dal Corno

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1

In Node.js it appears that you are allowed to do this:

data = "10";
switch(data){
    case "1": case "2": case "3": // Put multiple cases on the same
                                  // line to save vertical space.
        console.log("small");
        break;

    case "10": case "11": case "12":
        console.log("large");
        break;

    default:
        console.log("strange");
        break;
}

This makes for much more compact code in some cases.

Peter Mortensen

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answered Sep 1, 2015 at 9:12

AutomaticoAutomatico

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3

Here is one more easy-to-use switch case statement. which can fulfill your requirement. We can use the find method in the switch statement to get the desire output.

    switch(varname){
    case["afshin","saeed","larry"].find(name => name === varname):
        alert("Hey")
        break;
    default:
        alert('Default case');
        break;
}

answered Jan 11, 2023 at 12:38

Shoaib ArifShoaib Arif

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I use it like this:

switch (true){
     case /Pressure/.test(sensor): 
     {
        console.log('Its pressure!');
        break;
     }

     case /Temperature/.test(sensor): 
     {
        console.log('Its temperature!');
        break;
     }
}
Peter Mortensen

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answered Feb 21, 2018 at 12:40

Sergey VolkovSergey Volkov

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4

Some interesting methods. For me the best way to solve is using .find.

You can give an indication of what the multiple cases are by using a suitable name inside your find function.

switch (varName)
{
   case ["afshin", "saeed", "larry"].find(firstName => firstName === varName):
       alert('Hey');
       break;

   default:
       alert('Default case');
       break;
}

Other answers are more suitable for the given example but if you have multiple cases to me this is the best way.

answered Jun 25, 2021 at 10:30

Scott O'DeaScott O'Dea

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1

It depends. Switch evaluates once and only once. Upon a match, all subsequent case statements until 'break' fire no matter what the case says.

var onlyMen = true;
var onlyWomen = false;
var onlyAdults = false;
 
 (function(){
   switch (true){
     case onlyMen:
       console.log ('onlymen');
     case onlyWomen:
       console.log ('onlyWomen');
     case onlyAdults:
       console.log ('onlyAdults');
       break;
     default:
       console.log('default');
   }
})(); // returns onlymen onlywomen onlyadults
<script src="https://getfirebug.com/firebug-lite-debug.js"></script>

answered Mar 10, 2016 at 16:07

Ronnie SmithRonnie Smith

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1

You can use the 'in' operator...
It relies on the object/hash invocation, so it's as fast as JavaScript can be.

// Assuming you have defined functions f(), g(a) and h(a,b)
// somewhere in your code,
// you can define them inside the object, but...
// the code becomes hard to read. I prefer it this way.

o = { f1:f, f2:g, f3:h };

// If you use "STATIC" code can do:
o['f3']( p1, p2 )

// If your code is someway "DYNAMIC", to prevent false invocations
// m brings the function/method to be invoked (f1, f2, f3)
// and you can rely on arguments[] to solve any parameter problems.
if ( m in o ) o[m]()
Peter Mortensen

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answered Sep 6, 2014 at 12:51

ZEEZEE

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3

You can do this:

alert([
  "afshin", 
  "saeed", 
  "larry",
  "sasha",
  "boby",
  "jhon",
  "anna",
  // ...
].includes(varName)? 'Hey' : 'Default case')

or just a single line of code:

alert(["afshin", "saeed", "larry",...].includes(varName)? 'Hey' : 'Default case')

a little improvement from ErikE's answer

answered May 6, 2019 at 0:33

I can see there are lots of good answers here, but what happens if we need to check more than 10 cases? Here is my own approach:

 function isAccessible(varName){
     let accessDenied = ['Liam', 'Noah', 'William', 'James', 'Logan', 'Benjamin',
                        'Mason', 'Elijah', 'Oliver', 'Jacob', 'Daniel', 'Lucas'];
      switch (varName) {
         case (accessDenied.includes(varName) ? varName : null):
             return 'Access Denied!';
         default:
           return 'Access Allowed.';
       }
    }

    console.log(isAccessible('Liam'));
Peter Mortensen

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answered Sep 23, 2018 at 15:30

1

The problem with the above approaches, is that you have to repeat the several cases every time you call the function which has the switch. A more robust solution is to have a map or a dictionary.

Here is an example:

// The Map, divided by concepts
var dictionary = {
  timePeriod: {
    'month': [1, 'monthly', 'mensal', 'mês'],
    'twoMonths': [2, 'two months', '2 months', 'bimestral', 'bimestre'],
    'trimester': [3, 'trimesterly', 'quarterly', 'trimestral'],
    'semester': [4, 'semesterly', 'semestral', 'halfyearly'],
    'year': [5, 'yearly', 'annual', 'ano']
  },
  distance: {
    'km': [1, 'kms', 'kilometre', 'kilometers', 'kilometres'],
    'mile': [2, 'mi', 'miles'],
    'nordicMile': [3, 'Nordic mile', 'mil (10 km)', 'Scandinavian mile']
  },
  fuelAmount: {
    'ltr': [1, 'l', 'litre', 'Litre', 'liter', 'Liter'],
    'gal (imp)': [2, 'imp gallon', 'imperial gal', 'gal (UK)'],
    'gal (US)': [3, 'US gallon', 'US gal'],
    'kWh': [4, 'KWH']
  }
};

// This function maps every input to a certain defined value
function mapUnit (concept, value) {
  for (var key in dictionary[concept]) {
    if (key === value ||
      dictionary[concept][key].indexOf(value) !== -1) {
      return key
    }
  }
  throw Error('Uknown "'+value+'" for "'+concept+'"')
}

// You would use it simply like this
mapUnit("fuelAmount", "ltr") // => ltr
mapUnit("fuelAmount", "US gal") // => gal (US)
mapUnit("fuelAmount", 3) // => gal (US)
mapUnit("distance", "kilometre") // => km

// Now you can use the switch statement safely without the need
// to repeat the combinations every time you call the switch
var foo = 'monthly'
switch (mapUnit ('timePeriod', foo)) {
  case 'month':
    console.log('month')
    break
  case 'twoMonths':
    console.log('twoMonths')
    break
  case 'trimester':
    console.log('trimester')
    break
  case 'semester':
    console.log('semester')
    break
  case 'year':
    console.log('year')
    break
  default:
    throw Error('error')
}
Peter Mortensen

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answered Feb 25, 2019 at 14:28

One of the possible solutions is:

const names = {
afshin: 'afshin',
saeed: 'saeed',
larry: 'larry'
};

switch (varName) {
   case names[varName]: {
       alert('Hey');
       break;
   }

   default: {
       alert('Default case');
       break;
   }
}

answered Jul 11, 2019 at 14:54

JackkobecJackkobec

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2 Cleaner way to handle that
if (["triangle", "circle", "rectangle"].indexOf(base.type) > -1)
{
    //Do something
}else if (["areaMap", "irregular", "oval"].indexOf(base.type) > -1)
{
    //Do another thing
}

You can do that for multiple values with the same result

answered Sep 7, 2021 at 13:17

AbrahamAbraham

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If your case conditions are complex, many case value matches, or dynamic value match required, then it may be best to move that case matching logic to handler child functions.

In your case, if say you had thousands of usernames to match against for a security permissions check for example, this method is cleaner option, more extensible, exposing the high level multi-way branch logic without getting swamped in a long list of case statements.


    switch (varName)
    {     
      case checkPatternAdministrator(varName):
        alert('Hey');
        break;

      case checkPatternUserTypeA(varName):
        alert('Hey2');
        break;

      case checkPatternUserTypeB(varName):
        alert('Hey3');
        break;

      default:
        alert('Default case');
        break;
    }
 function checkPatternAdministrator(varName) {
    // Logic to check Names against list, account permissions etc.
    // return the varName if a match is found, or blank string if not
    var matchedAdministratorName = varName;

    return matchedAdministratorName;
  }

answered Dec 24, 2022 at 16:36

Another way of doing multiple cases in a switch statement, when inside a function:

function name(varName){
  switch (varName) {
     case 'afshin':
     case 'saeed':
     case 'larry':
       return 'Hey';
     default:
       return 'Default case';
   }
}

console.log(name('afshin')); // Hey
Peter Mortensen

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answered Jan 9, 2018 at 22:37

Morris SMorris S

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Just change the switch condition approach:

switch (true) {
    case (function(){ return true; })():
        alert('true');
        break;
    case (function(){ return false; })():
        alert('false');
        break;
    default:
        alert('default');
}
Peter Mortensen

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answered Dec 16, 2015 at 10:02

4

The switch statement is used to select one of many code blocks to execute based on a condition

  1. the value in the switch expression is compared to the different values provided
  2. if there is a match the code block related to it will be executed
  3. if there is no match the default block is executed

syntax:

switch(expression) {
  case x:
    // code block
    break;
  case y:
    // code block
    break;
  default:
    // code block
}

NOTE: It must be noted that if the break statement is omitted then the next block will be executed as well even if they does not match with switch expression. So don't forget to add the break statement at the end of each code block if you don't want to get the specified behaviour

A practical example: the following code returns the current day of the week in strings based on an integer (provided by 'new Date().getDay()')

switch (new Date().getDay()) {
  case 0:
    day = "Sunday";
    break;
  case 1:
    day = "Monday";
    break;
  case 2:
     day = "Tuesday";
    break;
  case 3:
    day = "Wednesday";
    break;
  case 4:
    day = "Thursday";
    break;
  case 5:
    day = "Friday";
    break;
  case 6:
    day = "Saturday";
}

the code samples were taken from W3Schools

answered Jan 30, 2023 at 13:11

1
<head>
    <meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
    <title>Example1</title>
    <link rel="stylesheet" href="css/style.css" >
    <script src="js/jquery-1.11.3.min.js" type="text/javascript"></script>
    <script>
        function display_case(){
            var num =   document.getElementById('number').value;

                switch(num){

                    case (num = "1"):
                    document.getElementById("result").innerHTML = "You select day Sunday";
                    break;

                    case (num = "2"):
                    document.getElementById("result").innerHTML = "You select day  Monday";
                    break;

                    case (num = "3"):
                    document.getElementById("result").innerHTML = "You select day  Tuesday";
                    break;

                    case (num = "4"):
                    document.getElementById("result").innerHTML = "You select day  Wednesday";
                    break;

                    case (num = "5"):
                    document.getElementById("result").innerHTML = "You select day  Thusday";
                    break;

                    case (num = "6"):
                    document.getElementById("result").innerHTML = "You select day  Friday";
                    break;

                    case (num = "7"):
                    document.getElementById("result").innerHTML = "You select day  Saturday";
                    break;

                    default:
                    document.getElementById("result").innerHTML = "You select day  Invalid Weekday";
                    break
                }

        }
    </script>
</head>
<body>
    <center>
        <div id="error"></div>
        <center>
            <h2> Switch Case Example </h2>
            <p>Enter a Number Between 1 to 7</p>
            <input type="text" id="number" />
            <button onclick="display_case();">Check</button><br />
            <div id="result"><b></b></div>
        </center>
    </center>
</body>

answered Oct 5, 2015 at 9:07

4

You could write it like this:

switch (varName)
{
   case "afshin": 
   case "saeed": 
   case "larry": 
       alert('Hey');
       break;

   default: 
       alert('Default case');
       break;
}         
Felipe Skinner

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answered Feb 24, 2016 at 11:37

Tim AnishereTim Anishere

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1

For me this is the simplest way:

switch (["afshin","saeed","larry"].includes(varName) ? 1 : 2) {
   case 1:
       alert('Hey');
       break;

   default:
       alert('Default case');
       break;
}
Peter Mortensen

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answered Nov 21, 2019 at 7:29

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