Function Command

Command(options: CommandOptions): (commandClass: CommandClass) => void

Decorator to register a class as a command with a unique identifier.

The @Command decorator marks a class as a command and assigns it a unique ID that can be used for command lookup, registration, and execution. This decorator is essential for the command pattern implementation and enables type-safe command creation through the CommandRegistry.

Parameters

options: CommandOptions
A CommandOptions object containing the unique command ID

Returns (commandClass: CommandClass) => void

Decorator function that registers the command class

Example: Basic command definition

import { AnyCommand, Command } from '@limetech/lime-web-components';

@Command({ id: 'generate-report' })
class GenerateReportCommand implements AnyCommand {
    public reportType: string;

    // Dates travel as ISO strings. A Date instance does not survive
    // serialization, and the platform may serialize a command.
    public startDate: string;
    public endDate: string;
}

const command = new GenerateReportCommand();
command.reportType = 'sales';
command.startDate = '2024-01-01';
command.endDate = '2024-03-31';

Example: Single-object command with context

import {
    Command,
    LimeObjectCommand,
    LimeObjectContext,
} from '@limetech/lime-web-components';

// The platform instantiates a command without arguments and then assigns the
// properties, so a command class declares no constructor.
@Command({ id: 'send-email' })
class SendEmailCommand implements LimeObjectCommand {
    public context: LimeObjectContext;
    public subject: string;
    public body: string;
}

const command = new SendEmailCommand();
command.context = { limetype: 'person', id: 42 };
command.subject = 'Meeting Invitation';
command.body = 'Please join us for a meeting...';

Example: Bulk command with filter

import {
    Command,
    Expression,
    LimeObjectBulkCommand,
    LimeTypeContext,
} from '@limetech/lime-web-components';

@Command({ id: 'export-to-excel' })
class ExportToExcelCommand implements LimeObjectBulkCommand {
    public context: LimeTypeContext;
    public filter: Expression | null;
    public includeRelations = false;
}

const command = new ExportToExcelCommand();
command.context = { limetype: 'deal', id: null };
command.filter = null;

Example: Register in the CommandRegistry for type safety

import {
    Command,
    Expression,
    LimeObjectBulkCommand,
    LimeObjectCommand,
    LimeObjectContext,
    LimeTypeContext,
    PlatformServiceName,
} from '@limetech/lime-web-components';

@Command({ id: 'generate-pdf-report' })
class GeneratePdfReportCommand {
    public reportType: string;
    public includeCharts: boolean;
}

@Command({ id: 'archive-deal' })
class ArchiveDealCommand implements LimeObjectCommand {
    public context: LimeObjectContext;
    public reason: string;
}

@Command({ id: 'bulk-update-status' })
class BulkUpdateStatusCommand implements LimeObjectBulkCommand {
    public context: LimeTypeContext;
    public filter: Expression | null;
    public newStatus: string;
}

declare module '@limetech/lime-web-components' {
    interface CommandRegistry {
        'generate-pdf-report': GeneratePdfReportCommand;
        'archive-deal': ArchiveDealCommand;
        'bulk-update-status': BulkUpdateStatusCommand;
    }
}

const commandBus = platform.get(PlatformServiceName.CommandBus);

const command = commandBus.createCommand({
    id: 'generate-pdf-report',
    params: { reportType: 'monthly', includeCharts: true },
});

await commandBus.handle(command);