React command hooks

A generated command’s static .use() method creates a command instance for a mounted component, configures it from the nearest Arc context, and registers it with the nearest command scope.

Return tuple

Position	Value	Contract
0	command	Generated instance, properties, execution, and change tracking
1	setValues	Updates supplied content properties and requests a React render
2	clearValues	Assigns undefined to all content properties and requests a render; does not reset the baseline

Omit unused trailing tuple values when destructuring. Do not treat the tuple itself as a command.

With initial values

Pass an explicit content object to seed values and baseline when the hook creates its instance. Initial values are not reapplied on later renders. Required generated properties are not automatically initialized; an identity, quantity, or other required value must come from your application.

This illustrative one-operation editor assumes a generated RenameAccount command with string accountId and name properties. If your backend uses a Guid-based concept, use the generated Fundamentals Guid type instead of a string:

import { useState } from 'react';
import { RenameAccount } from './generated/RenameAccount';

export function RenameAccountForm({ accountId, name }: { accountId: string; name: string }) {
    const [command, setValues] = RenameAccount.use({ accountId, name });
    const [saving, setSaving] = useState(false);
    const [message, setMessage] = useState('');

    async function save() {
        setSaving(true);
        try {
            const result = await command.execute();
            setMessage(result.isSuccess ? 'Saved.' : 'Could not save. Check your inputs and permissions.');
        } finally {
            setSaving(false);
        }
    }

    return (
        <form onSubmit={event => { event.preventDefault(); void save(); }}>
            <label>Name<input value={command.name ?? ''} disabled={saving}
                onChange={event => setValues({ name: event.target.value })} /></label>
            <button disabled={saving}>Save</button>
            <p role="status">{message}</p>
        </form>
    );
}

Key/remount the editor when switching accounts, or deliberately load a new baseline after deciding what to do with edits. See data binding for query-fed forms and reset semantics.

React re-rendering

Use the tuple setter for reliable per-edit rendering. Generated setters notify property tracking, but raw assignment does not reliably rerender every edit while hasChanges remains true. The hook does not automatically validate each assignment or provide an execution-loading state; use explicit state as above or CommandForm.

hasChanges compares draft content with the baseline. It is not an edit revision, a server-save status, or a guaranteed retry gate after failure. Current execution snapshots truthy values after completed server requests even when unsuccessful; see baseline limitations.

Available operations

• execute(allowedSeverity?, ignoreWarnings?) validates and attempts execution; inspect its CommandResult.
• validate() provides preflight feedback, potentially returning locally before server authorization.
• validateClientSide() checks local rules synchronously.
• setInitialValues(content) accepts explicit values as the baseline.
• revertChanges() restores baseline values.

Continue with validation, command scopes, or imperative usage.