fnguard provides something similar to an Erlang-style "function guard". Inside the function, the parameter types are specified and, at runtime, if one of the params is wrong, and error is thrown and with a message explaining which parameter failed and a stack trace started from the call to fnguard.
The function used for 'isobj' returns false for array, date, null, regexp and other not-object things that return 'object' from typeof experessions.
Here's an example of its usage
gethtml = (session, config, templatename, dataarr) => {
fnguard.isobj(session, config).isstr(templatename).isarr(dataarr)
// continue
}fnguard is useful when refactoring bigger javascript codebases for which you have no unit-tests. Or highly dynamic sources which are difficult to type check. Run the tests or look at the source code (small) to understand how it handles comparison.
A negation function prefixed with isnot is provided for each 'is' function, for example:
spec.isnotnum = function (n) {
return !spec.isnum(n)
}Todo:
- would be great if fnguard could use custom types (similar to how Erlang does this)
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