Booting

By default, a concern class is ONLY instantiated when you interact with its properties or methods, which have been "aliased" into a target class (aka. lazy booting).

class ContactsApi extends AbstractConcern {
    get users() { /* ...not shown here... */}
}

@use(ContactsApi) // Concern is NOT instantiated
class UsersRegistry {}

const users = (new UsersRegistry()).users; // Concern is instantiated

Manual Booting

You can use the bootConcerns() utility to manually boot concerns. It accepts the following arguments:

• instance: object|Owner - The target class instance that uses the concerns.
• ...concerns: ConcernConstructor[] - List of concern classes to instantiate (aka. boot).

import { use, bootConcerns } from "@aedart/support/concerns";

@use(
    ConcernA,
    ConcernB,
    ConcernC,
)
class Target {
    constructor() {
        bootConcerns(this, ConcernA, ConcernB);
    }
}

const instance = new Target(); // ConcernA and ConcernB are instantiated

warning

If you attempt to boot a concern that has already been booted, a BootError will be thrown!

To determine if a concern has already been booted, use the concern container's hasBooted() method.

import {
    getContainer,
    bootConcerns
} from "@aedart/support/concerns";

class Record extends ApiService {
    constructor() {
        super();
        
        if (!getContainer(this).hasBooted(ApiConnection)) {
            bootConcerns(this, ApiConnection);
        }
    }
}

See Manual interaction for details.

Boot All Concerns

If you wish to boot all concerns, use the bootAllConcerns() utility.

import { use, bootAllConcerns } from "@aedart/support/concerns";

@use(
    ConcernA,
    ConcernB,
    ConcernC,
)
class Target {
    constructor() {
        bootAllConcerns(this);
    }
}

const instance = new Target(); // All concerns are initialised