Switch case with conditions

Question

Am I writing the correct switch case   var cnt       div1 p   length                  alert cnt                   switch  cnt                        case  cnt  gt   10  amp  amp  cnt  lt   20                           alert  10                            break                      case  cnt  gt   21  amp  amp  cnt  lt   30                          alert  21                            break                      case  cnt  gt   31  amp  amp  cnt  lt   40                  alert  31                            break                      default                          alert   gt 41                        For some reason  the alert does not occur when the conditions are matched

User · Answer

Ok it is late but in case you or someone else still want to you use a switch or simply have a better understanding of how the switch statement works.

What was wrong is that your switch expression should match in strict comparison one of your case expression. If there is no match it will look for a default. You can still use your expression in your case with the && operator that makes Short-circuit evaluation.

Ok you already know all that. For matching the strict comparison you should add at the end of all your case expression && cnt.

Like follow:

switch(mySwitchExpression)
case customEpression && mySwitchExpression: StatementList
.
.
.
default:StatementList

_x000D_

var cnt = $("#div1 p").length;
alert(cnt);
switch (cnt) {
case (cnt >= 10 && cnt <= 20 && cnt):
    alert('10');
    break;
case (cnt >= 21 && cnt <= 30 && cnt):
    alert('21');
    break;
case (cnt >= 31 && cnt <= 40 && cnt):
    alert('31');
    break;
default:
    alert('>41');
}

_x000D_

<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>
<div id="div1">
<p> p1</p>
<p> p2</p>
<p> p3</p>
<p> p3</p>
<p> p4</p>
<p> p5</p>
<p> p6</p>
<p> p7</p>
<p> p8</p>
<p> p9</p>
<p> p10</p>
<p> p11</p>
<p> p12</p>
</div>

_x000D_

User · Answer

Something I came upon while trying to work a spinner was to allow for flexibility within the script without the use of a ton of if statements    Since this is a simpler solution than iterating through an array to check for a single instance of a class present it keeps the script cleaner  Any suggestions for cleaning the code further are welcome       next   click function            var imageToSlide       imageSprite       Get id of image          switch true                case  imageToSlide hasClass  pos1                     imageToSlide removeClass  pos1   addClass  pos2                    break              case  imageToSlide hasClass  pos2                     imageToSlide removeClass  pos2   addClass  pos3                    break              case  imageToSlide hasClass  pos3                     imageToSlide removeClass  pos3   addClass  pos4                    break              case  imageToSlide hasClass  pos4                     imageToSlide removeClass  pos4   addClass  pos1

User · Answer

Switch case is every help full instead of if else statement         switch      id  btnSave    val              case  Search               saveFlight                break          case  Update               break          case  Delete               break          default              break

User · Answer

This should work with this    var cnt       div1 p   length               switch  true                    case  cnt  gt   10  amp  amp  cnt  lt   20                       alert  10                        break                  case  cnt  gt   21  amp  amp  cnt  lt   30                      alert  21                        break                  case  cnt  gt   31  amp  amp  cnt  lt   40                       break                  default                      alert   gt 41

User · Answer

function date conversion start date       var formattedDate   new Date start date       var d   formattedDate getDate        var m    formattedDate getMonth        var month      m    1      JavaScript months are 0-11     switch  m            case 1                month  Jan               break                    case 2                month  Feb               break                    case 3                month  Mar               break                    case 4                month  Apr               break                    case 5                month  May               break                    case 6                month  Jun               break                    case 7                month  Jul               break                    case 8                month  Aug               break                    case 9                month  Sep               break                    case 10                month  Oct               break                    case 11                month  Nov               break                    case 12                month  Dec               break                      var y   formattedDate getFullYear        var now date d    -    month    -    y      return now date

User · Answer

A switch works by comparing what is in switch   to every case   switch  cnt        case 1           case 2           case 3           works like   if  cnt    1      if  cnt    2      if  cnt    3        Therefore  you can t have any logic in the case statements   switch  cnt        case  cnt  gt   10  amp  amp  cnt  lt   20           works like  if  cnt     cnt  gt   10  amp  amp  cnt  lt   20         and that s just nonsense      Use if        else if        else     instead

User · Answer

You should not use switch for this scenario   This is the proper approach   var cnt       div1 p   length   alert cnt    if  cnt  gt   10  amp  amp  cnt  lt   20       alert  10      else if  cnt  gt   21  amp  amp  cnt  lt   30       alert  21      else if  cnt  gt   31  amp  amp  cnt  lt   40       alert  31      else       alert   gt 41

User · Answer

What you are doing is to look for  0  or  1  results    cnt    10  amp  amp  cnt  lt   20  returns either true or false   --edit-- you can t use case with boolean  logic  experessions  The statement cnt    10 returns zero for false or one for true  Hence  it will we case 1  or case 0  which will never match to the length  --edit--

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