JavaScript function with optional parameters [duplicate]

Answer 1

You can check if parameters are defined and hard code that into your functions.

e.g.

 var preDefined = function(param) { 
    if(param === undefined) { 
        param = preDefinedValue
     }
     /* Rest of code goes here */
 }

ETA:

ES6 was allows for default parameter values (was unaware of this when I posted the answer).

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