CODEWITHSUNDEEP
javascript
user695663
user695663

Reputation: 12356

How to return values in javascript

I have a javascript function:

function myFunction(value1,value2,value3)
{
     //Do stuff and 

     value2=somevalue2 //to return
     value3=somevalue3 //to return
}

function call in Code: ....

myFunction("1",value2,value3);

if(value2 && value3)
{
//Do some stuff
}

in this scenario how to pass value2 and value3 to the called method or how to return values in Java script.

Upvotes: 52

Views: 288129

Answers (8)

raj peer
raj peer

Reputation: 718

Its very simple. Call one function inside another function with parameters.

 function fun1()
  {
    var a=10;
    var b=20;

    fun2(a,b); //calling function fun2() and passing 2 parameters
  }
       
 function fun2(num1,num2)
  {
    var sum;
    sum = num1+num2;
    return sum;
  }
    
fun1(); //trigger function fun1

Upvotes: 1

pgreen2
pgreen2

Reputation: 3651

The answers cover things very well. I just wanted to point out that the mechanism of out parameters, as described in the question isn't very javascriptish. While other languages support it, javascript prefers you to simply return values from functions.

With ES6/ES2015 they added destructuring that makes a solution to this problem more elegant when returning an array. Destructuring will pull parts out of an array/object:

function myFunction(value1)
{
    //Do stuff and 
    return [somevalue2, sumevalue3]
}

var [value2, value3] = myFunction("1");

if(value2  && value3)
{
    //Do some stuff
}

Upvotes: 0

Joomler
Joomler

Reputation: 2798

The return statement stops the execution of a function and returns a value from that function.

While updating global variables is one way to pass information back to the code that called the function, this is not an ideal way of doing so. A much better alternative is to write the function so that values that are used by the function are passed to it as parameters and the function returns whatever value that it needs to without using or updating any global variables.

By limiting the way in which information is passed to and from functions we can make it easier to reuse the same function from multiple places in our code.

JavaScript provides for passing one value back to the code that called it after everything in the function that needs to run has finished running.

JavaScript passes a value from a function back to the code that called it by using the return statement. The value to be returned is specified in the return keyword.

Upvotes: 1

Chris Kooken
Chris Kooken

Reputation: 33870

Javascript is duck typed, so you can create a small structure. 

function myFunction(value1,value2,value3)
{         
     var myObject = new Object();
     myObject.value2 = somevalue2;
     myObject.value3 = somevalue3;
     return myObject;
}


var value = myFunction("1",value2,value3);

if(value.value2  && value.value3)
{
//Do some stuff
}

Upvotes: 11

ezmilhouse
ezmilhouse

Reputation: 9121

I would prefer a callback solution: Working fiddle here: http://jsfiddle.net/canCu/

function myFunction(value1,value2,value3, callback) {

    value2 = 'somevalue2'; //to return
    value3 = 'somevalue3'; //to return

    callback( value2, value3 );

}

var value1 = 1;
var value2 = 2;
var value3 = 3;

myFunction(value1,value2,value3, function(value2, value3){
    if (value2 && value3) {
        //Do some stuff
        alert( value2 + '-' + value3 );
    }    
});

Upvotes: 2

McStretch
McStretch

Reputation: 20645

You can return an array, an object literal, or an object of a type you created that encapsulates the returned values.

Then you can pass in the array, object literal, or custom object into a method to disseminate the values.

Object example:

function myFunction(value1,value2,value3)
{
     var returnedObject = {};
     returnedObject["value1"] = value1;
     returnedObject["value2"] = value2;
     return returnedObject;
}

var returnValue = myFunction("1",value2,value3);

if(returnValue.value1  && returnValue.value2)
{
//Do some stuff
}

Array example:

function myFunction(value1,value2,value3)
{
     var returnedArray = [];
     returnedArray.push(value1);
     returnedArray.push(value2);
     return returnedArray;
}

var returnValue = myFunction("1",value2,value3);

if(returnValue[0]  && returnValue[1])
{
//Do some stuff
}

Custom Object:

function myFunction(value1,value2,value3)
{
     var valueHolder = new ValueHolder(value1, value2);
     return valueHolder;
}

var returnValue = myFunction("1",value2,value3);

// hypothetical method that you could build to create an easier to read conditional 
// (might not apply to your situation)
if(returnValue.valid())
{
//Do some stuff
}

I would avoid the array method because you would have to access the values via indices rather than named object properties.

Upvotes: 70

rob
rob

Reputation: 10119

function myFunction(value1,value2,value3)
{         
     return {val2: value2, val3: value3};
}

Upvotes: 6

no.good.at.coding
no.good.at.coding

Reputation: 20371

It's difficult to tell what you're actually trying to do and if this is what you really need but you might also use a callback:

function myFunction(value1,callback)
{
     //Do stuff and 

     if(typeof callback == 'function'){
        callback(somevalue2,somevalue3);
    }
}


myFunction("1", function(value2, value3){
    if(value2 && value3)
    {
    //Do some stuff
    }
});

Upvotes: 2

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