When creating a JavaScript function with multiple arguments, I am always confronted with this choice: pass a list of arguments vs. pass an options object.
For example I am writing a function to map a nodeList to an array:
function map(nodeList, callback, thisObject, fromIndex, toIndex){
...
}
I could instead use this:
function map(options){
...
}
where options is an object:
options={
nodeList:...,
callback:...,
thisObject:...,
fromIndex:...,
toIndex:...
}
Which one is the recommended way? Are there guidelines for when to use one vs. the other?
[Update] There seems to be a consensus in favor of the options object, so I'd like to add a comment: one reason why I was tempted to use the list of arguments in my case was to have a behavior consistent with the JavaScript built in array.map method.
Like many of the others, I often prefer passing an options object to a function instead of passing a long list of parameters, but it really depends on the exact context.
I use code readability as the litmus test.
For instance, if I have this function call:
checkStringLength(inputStr, 10);
I think that code is quite readable the way it is and passing individual parameters is just fine.
On the other hand, there are functions with calls like this:
initiateTransferProtocol("http", false, 150, 90, null, true, 18);
Completely unreadable unless you do some research. On the other hand, this code reads well:
initiateTransferProtocol({
"protocol": "http",
"sync": false,
"delayBetweenRetries": 150,
"randomVarianceBetweenRetries": 90,
"retryCallback": null,
"log": true,
"maxRetries": 18
});
It is more of an art than a science, but if I had to name rules of thumb, use an options parameter if: