Register, verify and compose "contracts" (classes) to allow for contract checks with class compositions.
As Kontract is a scoped package, the scope needs to be provided for both the installation and usage
$ npm install --save @konfirm/kontract
The Kontract component exposes three functions; register, compose and has.
Register a class extender as Kontract, this is a required step to be able to determine the implementation later on using has
const { register } = require('@konfirm/kontract');
const Foo = register(
(superclass) =>
class extends superclass {
get foo() {
return 'I am foo';
}
}
);
const Bar = register(
(superclass) =>
class extends superclass {
get bar() {
return 'I am bar';
}
}
);Compose a new class using class extender functions, if these are registered before, they will be detectable. If the very first argument is a class (instead of an extender function) that class will be used as base class.
const { compose } = require('@konfirm/kontract');
// assuming Foo and Bar from the register example
const FooBar = compose(
Foo,
Bar
);Has determines whether the provided target (which can be both a class or an instance) was extended by all of the provided extenders.
const { has } = require('@konfirm/kontract');
// assuming Foo and Bar from the register example
// assuming FooBar from the compose example
const foobar = new FooBar();
console.log(has(FooBar, Foo)); // true
console.log(has(FooBar, Bar)); // true
console.log(has(FooBar, Foo, Bar)); // true
if (has(foobar, Foo)) {
console.log(foobar.foo); // 'I am foo'
}
if (has(foobar, Bar)) {
console.log(foobar.bar); // 'I am bar'
}MIT License Copyright (c) 2019 Rogier Spieker (Konfirm)
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