This is a simple wrapper to Angus Croll's
typeOf
function defined in his article
Fixing the Javascript typeof operator.
Packaged as a module, sniff is ultraconvenient.
Additionally, it includes a subsequent test to determine whether a function
is a functional prototype, and therefore something that would be suitable
for calling with the new
operator. A value of prototype
is returned
from the function in event that:
-
the target has been detected as a
function
through Angus's previous logic -
the
prototype
of the function has some keys defined on it. While this is not a conclusive test (suggestions definitely welcome) I think it covers most of the cases where people are using JS prototypes in their code.
A small helper has been added to sniff to assist with the process of determining the function signature that a function has been called with. This code was written to help with those cases where you have a function that might be called with a variety of different combinations and permutations.
In simple cases, while you might do something like the following:
function example(name, opts, callback) {
if (typeof opts == 'function') {
callback = opts;
opts = {};
}
// rest of your function here
}
This can get tiresome and somewhat error prone when you have more
complicated functions. This is where the sniff.args
helper can come in
handy.
For example, this next function is designed to be called with just a name, or a name and an age, or name, age and callback, etc, etc. While writing a function like this would probably generally be discouraged in JS every now and again they are needed.
Anyway, let's take a look:
var sniff = require('sniff');
function example(name, age, opts, callback) {
// first analyse the arguments and get a matcher function
var matchSig = sniff.args(arguments);
// check for the name, age and callback case
if (matchSig('string', 'number|string', 'function')) {
// remap opts
callback = opts;
opts = {};
}
// or the name, opts, function case
else if (matchSig('string', 'object', 'function')) {
// remap age, opts, and the callback
callback = opts,
opts = age;
age = null;
}
}
NOTE: The sniff.args
function helper is deprecated, as I believe
this can probably be done a better way, and will have a look at it one
day...
Copyright (c) 2013 Damon Oehlman damon.oehlman@gmail.com
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