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Switch statement for multiple cases in JavaScript

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.

Sad that this syntax is not working :(

u
user229044

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');
}

Somehow it works for me in Chrome, in the javascript console: switch('10') { case 1, '10': console.log('ok') } prints ok
@nafg: Try switch(1). The label here is just a comma expression.
@Barney No, without the break you can fall through to the next case.
@Seiyira by definition, there is no next case after the last. Besides, it's a default.
P
Peter Mortensen

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);

@believesInSanta it's literally just normal case fallthrough with weird formatting (spaces instead of newlines)
You also can use case (1||2||3): instead of case 1: case 2: case 3:
case 1: case 2: case 3: worked for me and thanks, but @kasun Your solution does'nt work.
just an fyi, I tried @Kasun's method in TS, and it didn't work for me (I'm aware that OP wanted the solution in JS)
The reason why @KasunHasanga's suggested solution doesn't work is because case (1||2||3): is equivalent to case 1: (since 1||2||3 evaluates to 1).
e
elclanrs

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();

I definitely prefer this version. Fall through is a bug-prone feature of switch ... case. It's too easy to forget a break statement, and if you use fall through intentionally, those forgotten break statements can be very hard to spot. This method lookup version also has lots of great features that switch ... case lacks, such as dynamic extensibility, or the ability to completely replace the object to accomplish mode switching. It's also easier to keep cleanly organized, and can lead to more maintainable code. See ericleads.com/2012/12/switch-case-considered-harmful
I always add a comment //fallthrough in place of break whenever I intentionally omit the break. That helps to identify when it's a mistake and when it's intentional.
Intuitive approach. However, for readability, I'd recommend to use the native switch statement.
One can always scratch the left ear passing its right hand through the back of the neck... (sorry for my english, I mean: "one can always complicate things as much as possible...in this case, avoiding the switch statement in favor of this complicated solution doesn't seem to be the right thing to do...)
I'm truly amazed how this has gotten 34 up votes. In terms of readability and maintainability, this is absolutely horrific. If I want to see what conditions will trigger something, a case statement is incredibly simple and easy to see by looking at the labels. On the other hand, your version would require someone read pretty much every single line and see what you assigned where. This also gets even worse the more cases you want to match.
G
Geo

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


It's a common technique in a pletora of languages, not bound to JS
P
Peter Mortensen

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');

}

E
ErikE

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.


What is the benefit of this over a switch?
@BryceSnyder the difference between an expression and a statement? Less typing? Fewer vertical lines consumed? Greater expressive power through succinctness and density of representation? Better semantics through the includes word? Take your pick.
The benefit for me is, i can use the array from an external config source and after the array is changed externally the code still works.
This is my preferred option, these blocks of case options seem crazy, includes can use the original array instead of extracting elements individually.
This is a pretty reliable option, the only drawback is that it isn't as readable as a switch statement.
P
Peter Mortensen

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');
}

P
Peter Mortensen

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...


not yet tested but it would be interesting to modify varName inside the case expression, expect that varName is cached thou.
P
Peter Mortensen

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.


I think the syntax is the same as other JS environments.
@AfshinMehrabani It might be, I have only tested it in nodejs context.
Yes. I like save vertical space!
P
Peter Mortensen

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;
     }
}

You don't need to use the g flag, since you're only using the regexes once and throwing them away. In fact, if you were keeping them outside the function, the g flag would harm you by trying to match from a non-0 index on subsequent .test(s. I also fixed a typo where the switch case was on sensor variable and not true constant for matching boolean expressions. See the edit.
I used this format to test against file types. Ex: case /officedocument/.test(type) && /presentation/.test(type): iconClass = "far fa-file-powerpoint red"; break;
This is probably the best method of checking the input. See next comment for suggested edit.
R
Ronnie Royston

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


Historically, switch is a variation of the (in)famous goto statement. The idea is that you go to one of these labels, and then continue. That is, the labels represent entry points; if you want to exit, you have to do it yourself, with either the break statement or possibly a return statement if you’re inside a function.
P
Peter Mortensen

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]()

how does this relate to switch? can you clarify it?
why would you want to make your code "hard to read". The first thing I was told as a programmer was to write code with the mindset that the next person reading your code is an axe wielding serial killer and he hates not being able to understand code.
Hi Matt... I'm presenting it here as a proof of concept... anyway this form provides you more funcionality and flexibility... and you only use it if you want... or if you find a constrain in your usual form of doing things... consider ir as one more tool in your programmer toolbox...
S
Scott O'Dea

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.


I like this approach. It also play's nicely with ESlint and other code formatters
D
Dedy Abdillah

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


P
Peter Mortensen

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'));

This is abuse of the switch statement. Just if (accessDenied.includes(varName)) return 'Access Denied!'; return 'Access Allowed.' is more than enough.
P
Peter Mortensen

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') }


J
Jackkobec

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;
   }
}

Q pls which #ecma is this?
Hi there. This is ES6
P
Peter Mortensen

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


A
Abraham

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


P
Peter Mortensen

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');
}

If you put true as the switch expression, in the "case" statement(s) you can evaluate whatever you want provided you return a boolean
I think what he meant is that you can put an expression inside the function, who will evaluate and return a dynamic value for the case, thus allowing all sorts of complex conditions
For this @StefanoFavero note you dont actually need a function, just (expression) in parenthesis, and the return value must be the input. See my answer
why you minused it?? I advocate this solution because it provides a flexibility for complex conditions. Even if you dont like funcs as conditions, you may replace them with you multiple conditions such as switch(true) { case (var1 === 0 && var2 === true): {} }
K
Kirandeep Singh
<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>

classic jquery inclusion :)
This is not how the switch statement is supposed to work. It’s just case "1":, not case (num = "1"):.
Why not put day value inside case and document.getElementById("result").innerHTML = ....outside the switch and add the day value result at the end?
@Xufox I love how he literally overwrites num but it still works because the switch has already been evaluated and the assignment yields the value. This is programming by mutation/machine learning at its finest.
F
Felipe Skinner

You could write it like this:

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

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

This is the same answer as everyone else, i will fix the " that you forgot, but think about deleting this.
P
Peter Mortensen

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;
}

How is this the “simplest” way? Just replace this with an if statement.
If yo uhave in the array 20 elements you'd need 20 if's. This way is good for many elements.
Not at all.. Look, you already have 3 elements in your array. All you'd need is populate that array with the extra values. What Sebastian is saying here is that your switch acts exactly like an if statement so you are totally wrong, plus you did not even consider the case "2", you just assumed default is your "else".