README
polymorf
Create a polymorphic function that dispatches to different handler functions based on the type of the parameters it is passed.
Example
var add = polymorf(
[Number, Number],
function (a, b) {
return a + b
},
[String, String],
function (a, b) {
// Don't concat
return parseFloat(a) + parseFloat(b)
}
)
add(2, 3) // 5
add('10', '12') // 22
API
polymorf([signature, handler] [, [signature, handler] ...])
Create a new polymorphic function. Arguments are signature, handler
pairs, where signature
is an array of types and handler
is the function to be called if the polymorphic function is called with arguments whose types match the signature.
Allowed types
The following types are permitted as values in the signature array.
- Object
- Function
- String
- Error
- Number
- Array
- Boolean
- RegExp
- Date
- null
- undefined
You can also pass your own custom types. Internally polymorf will check if values match the type in the signature using the instanceof
operator.
polymorf.Any
Use the polymorf.Any
type matcher to match any value.
fn.polymorf.add(signature, handler)
Given a polymorphic function fn
, a new handler for a signature can be dynamically added. e.g.
var doubler = polymorf()
try {
doubler(4) // Throws
} catch (er) {
console.error('No signatures to match against')
}
doubler.polymorf.add([Number], function (x) {
return x * 2
})
doubler(4) // 8
fn.polymorf.remove(signature)
Given a polymorphic function fn
, an existing handler for a signature can be dynamically removed.