d11n/uri-query

// eslint-disable-next-line max-params
(function main(DEFAULT_STRATEGY) {
    class Uri_query {
        constructor(...args) {
            return construct_uri_query.call(this, ...args);
        }
    }
    Uri_query.is_encoded = is_encoded;
    return module.exports = Object.freeze(Uri_query);

    // -----------

    function construct_uri_query(parsee, alter_params) {
        const this_uri_query = this;
        const strategy = DEFAULT_STRATEGY;
        Object.defineProperty(this_uri_query, 'toString', { value: to_string });
        if (undefined !== parsee && null !== parsee) {
            Object.assign(
                this_uri_query,
                parse_parsee(parsee, strategy, alter_params),
                ); // eslint-disable-line indent
        }
        return this_uri_query;

        // -----------

        function to_string() {
            return compose_query_string(this_uri_query, strategy, alter_params);
        }
    }
    function parse_parsee(parsee, strategy, alter_params) {
        let parsed_query_object;
        switch (true) {
            case 'string' === typeof parsee:
            case 'number' === typeof parsee:
            case 'boolean' === typeof parsee:
            case 'symbol' === typeof parsee:
                parsed_query_object
                    = parse_query_string(String(parsee), strategy)
                    ; // eslint-disable-line indent
                break;
            case 'object' === typeof parsee:
                parsed_query_object = parse_query_params(parsee, strategy);
                break;
        }
        if (parsed_query_object) {
            parsed_query_object = protect_proto(parsed_query_object);
            return alter_params
                ? alter_query_object('parse', parsed_query_object, alter_params)
                : parsed_query_object
                ; // eslint-disable-line indent
        }
        throw new TypeError([
            'URI queries must be constructed with a primitive value',
            'or an object',
            ].join(' ')); // eslint-disable-line indent
    }

    // -----------

    function parse_query_string(raw_query_string, strategy) {
        const trimmed_raw_query_string = raw_query_string.trim();
        if ([ '', '?', '#', '?#' ].includes(trimmed_raw_query_string)) {
            return {};
        }
        const hash_index = trimmed_raw_query_string.indexOf('#');
        /* eslint-disable indent */
        const query_string = trimmed_raw_query_string
            .substring(
                '?' === trimmed_raw_query_string.substring(0, 1) ? 1 : 0,
                -1 === hash_index ? undefined : hash_index,
                )
            .replace(/(?:^[&\s]+|[&\s]+$)/g, '') // trim white space and &'s
            .replace(/[&\s]*&[&\s]*/g, '&')
            ;
        /* eslint-enable indent */
        if ('' === query_string) {
            return {};
        }
        return strategy.parse_query_string(query_string);
    }

    function parse_query_params(raw_object, strategy) {
        const flattened_proto_object = {};
        // eslint-disable-next-line guard-for-in
        for (const key in raw_object) {
            const value = raw_object[key];
            switch (true) {
                case undefined === value:
                case null === value:
                case 'string' === typeof value:
                case 'number' === typeof value:
                case 'boolean' === typeof value:
                case 'symbol' === typeof value:
                case 'object' === typeof value:
                    flattened_proto_object[key] = value;
            }
        }
        return strategy.parse_query_params(flattened_proto_object);
    }

    function compose_query_string(query_object, strategy, alter_params) {
        const unsafe_query_object = unprotect_proto(query_object);
        const altered_object = alter_params
            ? alter_query_object('compose', unsafe_query_object, alter_params)
            : unsafe_query_object
            ; // eslint-disable-line indent
        return strategy.compose_query_string(altered_object);
    }

    // -----------

    function protect_proto(parsed_query_object) {
        const unsafe_keys = Object.getOwnPropertyNames(Object.prototype);
        const safe_query_object = Object.assign({}, parsed_query_object);
        for (const key of unsafe_keys) {
            '__proto__' !== key // __proto__ is ignored by javascript
                && undefined !== safe_query_object[key]
                && safe_query_object[key] !== Object.prototype[key]
                && protect_prop(key)
                ; // eslint-disable-line indent
        }
        return safe_query_object;

        // -----------

        function protect_prop(key) {
            safe_query_object[ `$$$${ key }` ] = safe_query_object[key];
            delete safe_query_object[key];
            return true;
        }
    }

    function unprotect_proto(parsed_query_object) {
        const unsafe_keys = Object.getOwnPropertyNames(Object.prototype);
        const unsafe_query_object = Object.assign({}, parsed_query_object);
        for (const unsafe_key of unsafe_keys) {
            const safe_key = `$$$${ unsafe_key }`;
            '__proto__' !== unsafe_key // __proto__ is ignored by javascript
                && undefined !== unsafe_query_object[safe_key]
                && unprotect_prop(unsafe_key, safe_key)
                ; // eslint-disable-line indent
        }
        return unsafe_query_object;

        // -----------

        function unprotect_prop(unsafe_key, safe_key) {
            unsafe_query_object[ unsafe_key ] = unsafe_query_object[safe_key];
            delete unsafe_query_object[safe_key];
            return true;
        }
    }

    // -----------

    function alter_query_object(mode, query_object, alter_params) {
        const altered_object = Object.assign({}, query_object);
        const query_keys = Object.keys(query_object);
        const alter_keys = Object.keys(alter_params);
        for (const key of alter_keys) {
            if (query_keys.includes(key)) {
                const alter_value = alter_params[key];
                /* eslint-disable indent */
                const perform_alteration
                    = 'parse' === mode ? 'function' === typeof alter_value
                        ? alter_value
                        : 'function' === typeof alter_value.parse
                            ? alter_value.parse
                            : dont_alter
                    : 'compose' === mode
                        ? 'function' === typeof alter_value.compose
                            ? alter_value.compose
                            : dont_alter
                    : dont_alter
                    ;
                /* eslint-ensable indent */
                altered_object[key] = perform_alteration(altered_object[key]);
            }
        }
        return altered_object;
    }

    function dont_alter(value) {
        return value;
    }

    // -----------

    function is_encoded(raw_uri_query) {
        return /^\??(?:[A-Za-z0-9-._~!$&'()*+,;=:@/?]|%[0-9A-F]{2})*(?:#.*)?$/
            .test(raw_uri_query)
            ; // eslint-disable-line indent
    }
}(
    require('./strategies/default'),
));