In javascript I am doing the following which works fine.
if (myVar == 25 || myVar == 26 || myVar == 27 || myVar == 28)
{
//do something
}
How can I shorten it? something like the following.
if (myVar IN ('25','26','27','28')) {
//do something
}
or
if(myVar.indexOf("25","26","27","28") > -1) ) {//do something}
You can use Array.indexOf(), it returns the first index at which a given element can be found in the array, or -1 if it is not present.
Use
var arr = [25, 26, 27, 28];
console.log(arr.indexOf(25) > -1);
console.log(arr.indexOf(31) > -1);Array.includes() method can also be used it returns boolean.
var arr = [25, 26, 27, 28];
console.log(arr.includes(25));
console.log(arr.includes(31));Just try with:
if ( [25, 26, 27, 28].indexOf(myVar) > -1 ) {}
Other way :
myVar = (myVar == parseInt(myVar) ? myVar : false); //to check if variable is an integer and not float
if ( myVar >= 25 && myVar <= 28){}
Edit based on the comment of Anthony Grist
This way works if you know what those values are going to be (i.e. they're not dynamic) and your array contains a series of consecutive numeric values.
> 24 && < 29 is even shorter :)
Since indexOf(), has some browser compatibility issues and requires an extra step (of comparing the result to -1), an alternative, cross-browser approach is the following jQuery utility method (if you include jQuery in your project) :
if($.inArray(myVar, [25, 26, 27, 28]) > -1) {
// ... do something ...
}
if ( [25, 26, 27, 28].indexOf(myVar) > -1 ) {}
Array.indexOf will work fine for all modern browsers(FF, Chrome, >IE8), just a word of caution is that Array.indexOf will not work for IE8. If you want to make it work in IE8 please use the below code:
window.onload = function() {
if (!Array.prototype.indexOf) {
Array.prototype.indexOf = function(elt /*, from*/) { var len = this.length >>> 0; var from = Number(arguments[1]) || 0; from = (from < 0) ? Math.ceil(from) : Math.floor(from); if (from < 0) { from += len; } for (; from < len; from++) { if (from in this && this[from] === elt){ return from; } } return -1;};
}
}
var validValues = [25, 26, 27, 28]
var myVar = 25
if (validValues.includes(myVar)) {
//do something
}
