index.js

'use strict';

const processFn = (fn, options) => function (...args) {
	const P = options.promiseModule;

	return new P((resolve, reject) => {
		if (options.multiArgs) {
			args.push((...result) => {
				if (options.errorFirst) {
					if (result[0]) {
						reject(result);
					} else {
						result.shift();
						resolve(result);
					}
				} else {
					resolve(result);
				}
			});
		} else if (options.errorFirst) {
			args.push((error, result) => {
				if (error) {
					reject(error);
				} else {
					resolve(result);
				}
			});
		} else {
			args.push(resolve);
		}

		fn.apply(this, args);
	});
};

module.exports = (input, options) => {
	options = Object.assign({
		exclude: [/.+(Sync|Stream)$/],
		errorFirst: true,
		promiseModule: Promise
	}, options);

	const objType = typeof input;
	if (!(input !== null && (objType === 'object' || objType === 'function'))) {
		throw new TypeError(`Expected \`input\` to be a \`Function\` or \`Object\`, got \`${input === null ? 'null' : objType}\``);
	}

	const filter = key => {
		const match = pattern => typeof pattern === 'string' ? key === pattern : pattern.test(key);
		return options.include ? options.include.some(match) : !options.exclude.some(match);
	};

	let ret;
	if (objType === 'function') {
		ret = function (...args) {
			return options.excludeMain ? input(...args) : processFn(input, options).apply(this, args);
		};
	} else {
		ret = Object.create(Object.getPrototypeOf(input));
	}

	for (const key in input) { // eslint-disable-line guard-for-in
		const property = input[key];
		ret[key] = typeof property === 'function' && filter(key) ? processFn(property, options) : property;
	}

	return ret;
};