Detect ESLint w/Stylistic quote style (untested)

detect-eslint-quote-style.js

import multimatch from 'multimatch'
import fs from 'node:fs';
import path from 'node:path';
import process from 'node:process';
import { tsImport } from 'tsx/esm/api';

const QUOTE_STYLES = ['double', 'single', 'backtick'];

function isJavaScriptFileGlob(globs) {
    return Boolean(multimatch('test.js', globs).length);
}

function isTypeScriptFileGlob(globs) {
    return Boolean(multimatch('test.ts', globs).length);
}

async function detectEslintQuoteStyle(cwd = process.cwd()) {
    const configFileCandidates = [
        'eslint.config.js',
        'eslint.config.mjs',
        'eslint.config.cjs',
        'eslint.config.ts',
        'eslint.config.mts',
        'eslint.config.cts'
    ];
    const configFile = configFileCandidates.find(candidate => fs.existsSync(path.join(cwd, candidate)));

    if (!configFile) {
        return null;
    }

    const configPath = path.join(cwd, configFile);
    const tsFileExtensions = ['.ts', '.mts', '.cts'];
    const isTsConfigFile = tsFileExtensions.some(extension => configFile.endsWith(extension));
    const config = isTsConfigFile
        ? await tsImport(configPath, import.meta.url)
        : await import(configPath);
    const relevantConfigSections = config.filter(section =>
        Boolean(
            section?.files?.length &&
            (
                isTsConfigFile
                    ? isTypeScriptFileGlob(section.files)
                    : isJavaScriptFileGlob(section.files)
            ) &&
            section.rules?.['@stylistic/quotes']
        )
    );

    if (relevantConfigSections) {
        const quotes = relevantConfigSections.at(-1).rules['@stylistic/quotes'];
        const eslintErrorAndWarnStates = ['warn', 1, 'error', 2];

        if (!Array.isArray(quotes) && eslintErrorAndWarnStates.includes(quotes)) {
            return 'double';
        } else if (Array.isArray(quotes) && quotes.length >= 2) {
            const quoteStyle = quotes.at(1);

            return QUOTE_STYLES.includes(quoteStyle)
                ? quoteStyle
                : null;
        }
    }

    return null;
}