Default values of parametrs for own functions in jquery

Question

I am writing my own jQuery functions. Is it possible to set the default values of the function parameters?

Solution 1

One way to do this is to check the parameters. For example:

function test(paramA) {
    if (paramA == null) {
        paramA = defaultValue;
    }
    // use paramA here
}

Another possibility is this:

function test() {
    var paramA = defaultValue;
    if (arguments.length == 1) {
        paramA = arguments[0];
    }
    // use paramA here
}

Solution 2

i can't vote right now but agree with color2life.

a = a || "something"

is probably the most concise and readable version.

Solution 3

You might want to check for undefined instead of null.

var f=function(param){
  if(param===undefined){
    // set default value for param
  }
}

Comments

[sev]

Thanks a lot. It is what I find.

[DemitryT]

Don't forget the semicolon at the end of the line. Even though JS will put those in for you where it can, it's good practice to do it yourself.

[KingOfHypocrites]

This will fail with booleans. If you pass in false, and your default value is true, it will always be set to true.

[KingOfHypocrites]

This will fail with booleans. If you pass in false, and your default value is true, it will always be set to true.