How do I force a client to call the build method at the end of the command chain?
const foo = new Foo();
foo.bar().a() // I want to make sure that the `build` method was called.
Here's my example:
interface IFoo {
bar(): IBar;
build(): string;
}
class Foo {
public commands;
constructor() {
this.commands = []
}
public bar(): any {
return new Bar(this);
}
public build(): any {
return this.commands.join(' ')
}
}
interface IBar {
a(): IFoo
}
class Bar {
private foo: Foo;
constructor(foo){
this.foo = foo;
}
public a(): IFoo {
this.foo.commands.push('something')
return
}
}
Like Peter said, just structure your API such that it provides no utility to a consumer except in the ways you desire:
class Base {
protected commands: string[];
constructor (commands?: string[]) {
this.commands = commands ?? [];
}
public build (): string {
return this.commands.join(' ');
}
private toString (): string {
return this.build();
}
private toJSON (): string[] {
return this.commands;
}
}
class Foo extends Base {
public bar (): Bar {
return new Bar(this.commands);
}
}
class Bar extends Base {
public a (): Foo {
this.commands.push('something');
return new Foo(this.commands);
}
}
// Use:
const foo = new Foo();
const bar = foo.bar();
const anotherFoo = foo.bar().a();
const command = anotherFoo.build();
anotherFoo.commands; /*
^^^^^^^^
Property 'commands' is protected and only accessible within class 'Base' and its subclasses.(2445) */
console.log(command); // "something"
console.log(JSON.stringify(anotherFoo)); // '["something"]'
console.log(String(anotherFoo)); // "something"