eslint-plugin-unicorn/rules/no-magic-array-flat-depth.js

More than 100 powerful ESLint rules

import {isMethodCall, isNumberLiteral} from './ast/index.js';
import {getCallExpressionTokens} from './utils/index.js';

const MESSAGE_ID = 'no-magic-array-flat-depth';
const messages = {
	[MESSAGE_ID]: 'Magic number as depth is not allowed.',
};

/** @param {import('eslint').Rule.RuleContext} context */
const create = context => ({
	CallExpression(callExpression) {
		if (!isMethodCall(callExpression, {
			method: 'flat',
			argumentsLength: 1,
			optionalCall: false,
		})) {
			return;
		}

		const [depth] = callExpression.arguments;

		if (!isNumberLiteral(depth) || depth.value === 1) {
			return;
		}

		const {sourceCode} = context;
		const {
			openingParenthesisToken,
			closingParenthesisToken,
		} = getCallExpressionTokens(sourceCode, callExpression);
		if (sourceCode.commentsExistBetween(openingParenthesisToken, closingParenthesisToken)) {
			return;
		}

		return {
			node: depth,
			messageId: MESSAGE_ID,
		};
	},
});

/** @type {import('eslint').Rule.RuleModule} */
const config = {
	create,
	meta: {
		type: 'suggestion',
		docs: {
			description: 'Disallow a magic number as the `depth` argument in `Array#flat(…).`',
			recommended: true,
		},
		messages,
	},
};

export default config;