base.js

import decodeComponent from 'decode-uri-component';
import splitOnFirst from 'split-on-first';
import {includeKeys} from 'filter-obj';

const isNullOrUndefined = value => value === null || value === undefined;

// eslint-disable-next-line unicorn/prefer-code-point
const strictUriEncode = string => encodeURIComponent(string).replace(/[!'()*]/g, x => `%${x.charCodeAt(0).toString(16).toUpperCase()}`);

const encodeFragmentIdentifier = Symbol('encodeFragmentIdentifier');

function encoderForArrayFormat(options) {
	switch (options.arrayFormat) {
		case 'index': {
			return key => (result, value) => {
				const index = result.length;

				if (
					value === undefined
					|| (options.skipNull && value === null)
					|| (options.skipEmptyString && value === '')
				) {
					return result;
				}

				if (value === null) {
					return [
						...result, [encode(key, options), '[', index, ']'].join(''),
					];
				}

				return [
					...result,
					[encode(key, options), '[', encode(index, options), ']=', encode(value, options)].join(''),
				];
			};
		}

		case 'bracket': {
			return key => (result, value) => {
				if (
					value === undefined
					|| (options.skipNull && value === null)
					|| (options.skipEmptyString && value === '')
				) {
					return result;
				}

				if (value === null) {
					return [
						...result,
						[encode(key, options), '[]'].join(''),
					];
				}

				return [
					...result,
					[encode(key, options), '[]=', encode(value, options)].join(''),
				];
			};
		}

		case 'colon-list-separator': {
			return key => (result, value) => {
				if (
					value === undefined
					|| (options.skipNull && value === null)
					|| (options.skipEmptyString && value === '')
				) {
					return result;
				}

				if (value === null) {
					return [
						...result,
						[encode(key, options), ':list='].join(''),
					];
				}

				return [
					...result,
					[encode(key, options), ':list=', encode(value, options)].join(''),
				];
			};
		}

		case 'comma':
		case 'separator':
		case 'bracket-separator': {
			const keyValueSep = options.arrayFormat === 'bracket-separator'
				? '[]='
				: '=';

			return key => (result, value) => {
				if (
					value === undefined
					|| (options.skipNull && value === null)
					|| (options.skipEmptyString && value === '')
				) {
					return result;
				}

				// Translate null to an empty string so that it doesn't serialize as 'null'
				value = value === null ? '' : value;

				if (result.length === 0) {
					return [[encode(key, options), keyValueSep, encode(value, options)].join('')];
				}

				return [[result, encode(value, options)].join(options.arrayFormatSeparator)];
			};
		}

		default: {
			return key => (result, value) => {
				if (
					value === undefined
					|| (options.skipNull && value === null)
					|| (options.skipEmptyString && value === '')
				) {
					return result;
				}

				if (value === null) {
					return [
						...result,
						encode(key, options),
					];
				}

				return [
					...result,
					[encode(key, options), '=', encode(value, options)].join(''),
				];
			};
		}
	}
}

function parserForArrayFormat(options) {
	let result;

	switch (options.arrayFormat) {
		case 'index': {
			return (key, value, accumulator) => {
				result = /\[(\d*)]$/.exec(key);

				key = key.replace(/\[\d*]$/, '');

				if (!result) {
					accumulator[key] = value;
					return;
				}

				if (accumulator[key] === undefined) {
					accumulator[key] = {};
				}

				accumulator[key][result[1]] = value;
			};
		}

		case 'bracket': {
			return (key, value, accumulator) => {
				result = /(\[])$/.exec(key);
				key = key.replace(/\[]$/, '');

				if (!result) {
					accumulator[key] = value;
					return;
				}

				if (accumulator[key] === undefined) {
					accumulator[key] = [value];
					return;
				}

				accumulator[key] = [...accumulator[key], value];
			};
		}

		case 'colon-list-separator': {
			return (key, value, accumulator) => {
				result = /(:list)$/.exec(key);
				key = key.replace(/:list$/, '');

				if (!result) {
					accumulator[key] = value;
					return;
				}

				if (accumulator[key] === undefined) {
					accumulator[key] = [value];
					return;
				}

				accumulator[key] = [...accumulator[key], value];
			};
		}

		case 'comma':
		case 'separator': {
			return (key, value, accumulator) => {
				const isArray = typeof value === 'string' && value.includes(options.arrayFormatSeparator);
				const isEncodedArray = (typeof value === 'string' && !isArray && decode(value, options).includes(options.arrayFormatSeparator));
				value = isEncodedArray ? decode(value, options) : value;
				const newValue = isArray || isEncodedArray ? value.split(options.arrayFormatSeparator).map(item => decode(item, options)) : (value === null ? value : decode(value, options));
				accumulator[key] = newValue;
			};
		}

		case 'bracket-separator': {
			return (key, value, accumulator) => {
				const isArray = /(\[])$/.test(key);
				key = key.replace(/\[]$/, '');

				if (!isArray) {
					accumulator[key] = value ? decode(value, options) : value;
					return;
				}

				const arrayValue = value === null
					? []
					: value.split(options.arrayFormatSeparator).map(item => decode(item, options));

				if (accumulator[key] === undefined) {
					accumulator[key] = arrayValue;
					return;
				}

				accumulator[key] = [...accumulator[key], ...arrayValue];
			};
		}

		default: {
			return (key, value, accumulator) => {
				if (accumulator[key] === undefined) {
					accumulator[key] = value;
					return;
				}

				accumulator[key] = [...[accumulator[key]].flat(), value];
			};
		}
	}
}

function validateArrayFormatSeparator(value) {
	if (typeof value !== 'string' || value.length !== 1) {
		throw new TypeError('arrayFormatSeparator must be single character string');
	}
}

function encode(value, options) {
	if (options.encode) {
		return options.strict ? strictUriEncode(value) : encodeURIComponent(value);
	}

	return value;
}

function decode(value, options) {
	if (options.decode) {
		return decodeComponent(value);
	}

	return value;
}

function keysSorter(input) {
	if (Array.isArray(input)) {
		return input.sort();
	}

	if (typeof input === 'object') {
		return keysSorter(Object.keys(input))
			.sort((a, b) => Number(a) - Number(b))
			.map(key => input[key]);
	}

	return input;
}

function removeHash(input) {
	const hashStart = input.indexOf('#');
	if (hashStart !== -1) {
		input = input.slice(0, hashStart);
	}

	return input;
}

function getHash(url) {
	let hash = '';
	const hashStart = url.indexOf('#');
	if (hashStart !== -1) {
		hash = url.slice(hashStart);
	}

	return hash;
}

function parseValue(value, options) {
	if (options.parseNumbers && !Number.isNaN(Number(value)) && (typeof value === 'string' && value.trim() !== '')) {
		value = Number(value);
	} else if (options.parseBooleans && value !== null && (value.toLowerCase() === 'true' || value.toLowerCase() === 'false')) {
		value = value.toLowerCase() === 'true';
	}

	return value;
}

export function extract(input) {
	input = removeHash(input);
	const queryStart = input.indexOf('?');
	if (queryStart === -1) {
		return '';
	}

	return input.slice(queryStart + 1);
}

export function parse(query, options) {
	options = {
		decode: true,
		sort: true,
		arrayFormat: 'none',
		arrayFormatSeparator: ',',
		parseNumbers: false,
		parseBooleans: false,
		...options,
	};

	validateArrayFormatSeparator(options.arrayFormatSeparator);

	const formatter = parserForArrayFormat(options);

	// Create an object with no prototype
	const returnValue = Object.create(null);

	if (typeof query !== 'string') {
		return returnValue;
	}

	query = query.trim().replace(/^[?#&]/, '');

	if (!query) {
		return returnValue;
	}

	for (const parameter of query.split('&')) {
		if (parameter === '') {
			continue;
		}

		const parameter_ = options.decode ? parameter.replace(/\+/g, ' ') : parameter;

		let [key, value] = splitOnFirst(parameter_, '=');

		if (key === undefined) {
			key = parameter_;
		}

		// Missing `=` should be `null`:
		// http://w3.org/TR/2012/WD-url-20120524/#collect-url-parameters
		value = value === undefined ? null : (['comma', 'separator', 'bracket-separator'].includes(options.arrayFormat) ? value : decode(value, options));
		formatter(decode(key, options), value, returnValue);
	}

	for (const [key, value] of Object.entries(returnValue)) {
		if (typeof value === 'object' && value !== null) {
			for (const [key2, value2] of Object.entries(value)) {
				value[key2] = parseValue(value2, options);
			}
		} else {
			returnValue[key] = parseValue(value, options);
		}
	}

	if (options.sort === false) {
		return returnValue;
	}

	// TODO: Remove the use of `reduce`.
	// eslint-disable-next-line unicorn/no-array-reduce
	return (options.sort === true ? Object.keys(returnValue).sort() : Object.keys(returnValue).sort(options.sort)).reduce((result, key) => {
		const value = returnValue[key];
		if (Boolean(value) && typeof value === 'object' && !Array.isArray(value)) {
			// Sort object keys, not values
			result[key] = keysSorter(value);
		} else {
			result[key] = value;
		}

		return result;
	}, Object.create(null));
}

export function stringify(object, options) {
	if (!object) {
		return '';
	}

	options = {encode: true,
		strict: true,
		arrayFormat: 'none',
		arrayFormatSeparator: ',', ...options};

	validateArrayFormatSeparator(options.arrayFormatSeparator);

	const shouldFilter = key => (
		(options.skipNull && isNullOrUndefined(object[key]))
		|| (options.skipEmptyString && object[key] === '')
	);

	const formatter = encoderForArrayFormat(options);

	const objectCopy = {};

	for (const [key, value] of Object.entries(object)) {
		if (!shouldFilter(key)) {
			objectCopy[key] = value;
		}
	}

	const keys = Object.keys(objectCopy);

	if (options.sort !== false) {
		keys.sort(options.sort);
	}

	return keys.map(key => {
		const value = object[key];

		if (value === undefined) {
			return '';
		}

		if (value === null) {
			return encode(key, options);
		}

		if (Array.isArray(value)) {
			if (value.length === 0 && options.arrayFormat === 'bracket-separator') {
				return encode(key, options) + '[]';
			}

			return value
				.reduce(formatter(key), [])
				.join('&');
		}

		return encode(key, options) + '=' + encode(value, options);
	}).filter(x => x.length > 0).join('&');
}

export function parseUrl(url, options) {
	options = {
		decode: true,
		...options,
	};

	let [url_, hash] = splitOnFirst(url, '#');

	if (url_ === undefined) {
		url_ = url;
	}

	return {
		url: url_?.split('?')?.[0] ?? '',
		query: parse(extract(url), options),
		...(options && options.parseFragmentIdentifier && hash ? {fragmentIdentifier: decode(hash, options)} : {}),
	};
}

export function stringifyUrl(object, options) {
	options = {
		encode: true,
		strict: true,
		[encodeFragmentIdentifier]: true,
		...options,
	};

	const url = removeHash(object.url).split('?')[0] || '';
	const queryFromUrl = extract(object.url);

	const query = {
		...parse(queryFromUrl, {sort: false}),
		...object.query,
	};

	let queryString = stringify(query, options);
	if (queryString) {
		queryString = `?${queryString}`;
	}

	let hash = getHash(object.url);
	if (object.fragmentIdentifier) {
		const urlObjectForFragmentEncode = new URL(url);
		urlObjectForFragmentEncode.hash = object.fragmentIdentifier;
		hash = options[encodeFragmentIdentifier] ? urlObjectForFragmentEncode.hash : `#${object.fragmentIdentifier}`;
	}

	return `${url}${queryString}${hash}`;
}

export function pick(input, filter, options) {
	options = {
		parseFragmentIdentifier: true,
		[encodeFragmentIdentifier]: false,
		...options,
	};

	const {url, query, fragmentIdentifier} = parseUrl(input, options);

	return stringifyUrl({
		url,
		query: includeKeys(query, filter),
		fragmentIdentifier,
	}, options);
}

export function exclude(input, filter, options) {
	const exclusionFilter = Array.isArray(filter) ? key => !filter.includes(key) : (key, value) => !filter(key, value);

	return pick(input, exclusionFilter, options);
}