marco-code-style

Marco's code style

Observed conventions, then confirmed. Every rule below came from reading 748 commits Marco authored, cross-checked by author-frequency per file, and then put to him directly in a 69-question interview covering naming, control flow, typing, React, state, server patterns, structure, comments, and tests.

Precedence. Project conventions win when they conflict with this file. Read the neighbouring files first. Where project documentation states a rule Marco's own code contradicts, follow the surrounding file, and follow this file for new modules he owns.

Scope. Mechanical rules (formatting, import order, casing, banned syntax) are lint config, not guidance; they live in eslint-recommendations.md in the ai-essentials repo. Cursor consumes the same material as file-scoped rules in rules/typescript-style.mdc, rules/react-components.mdc, rules/node-api-patterns.mdc, rules/testing-style.mdc, and rules/project-structure.mdc.

Where his stated preference overrides his existing code

Read these first. Following the code instead of the preference is the most likely way to get it wrong.

Rule	His code	His answer
Type name prefixes	no prefixes in Kibana (58 declarations)	I on interfaces, T on type aliases
Props interface	inline object type under ~4 props	always a named interface IXProps
Guard braces	12 brace-less single-line guards	always braces
Imperative loops	24 for…of for sequencing	declarative by default; imperative is a performance escape hatch
Abort signals	threaded through every call	only long-running or user-cancellable requests
Destructured params	past ~2 arguments	past 1 argument, and always once one is optional

Components

// Default form.
export function SignificantEventsPage({ tab, onTabChange }: ISignificantEventsPageProps) {
  // ...
}

// Arrow-const only for a one-expression wrapper.
export const AppHeader = (props: IAppHeaderProps) => <PageHeader {...props} />;