inheritfn v1.0.0

inheritfn

Prototypical inheritance for functions.

Enables you to wrap a function with another function without losing access to values defined on the original function.

inheritfn implements copy-on-write behaviour similarly to regular Object prototypical inheritance via Object.create.

Example

var inheritfn = require('inheritfn')

function original() {
  return original.value
}

function wrapper() {
  return wrapper.value
}

fncreate(original, wrapper)

original.value = 10

// wrapper inherits values from original
console.log(original()) // => 10
console.log(wrapper()) // => 10

// changing original.value changes wrapper.value
original.value = 20
console.log(wrapper()) // => 20
console.log(original()) // => 20

copy on write!

inheritfn implements copy-on-write behaviour similarly to regular Object prototypical inheritance via Object.create:

// write to wrapper.value
wrapper.value = 100

// wrapper.value becomes no longer linked to original
console.log(wrapper()) // => 100

// original is unchanged
console.log(original()) // => 20

• If a value on the original function changes, this is reflected on the new function.
• If you write to a key on the new function, access to the original function's value with the same key is shadowed by this new value.
• Unlike regular JavaScript prototypical inheritance, deleting a key on the new function will not restore access to the original function's key. You'll need to delete the key from newFn.__proxy__.

__proto__

To round out the prototypical inheritance 'simulation' a bit more.

wrapper.__proto__ == original // => true

See Also

• timoxley/beforefn
• timoxley/afterfn
• timoxley/guardfn

License

MIT