js utils

snips.ts

export function getPath(url: string)  {
    return url
    .replace(/^(http[s]?:)?\/\/[^/#?]+/, '') // remove origin
    .replace(/[?#].*$/, '') // remove querystring or hash
}


export function getUrlParams(url: string) : {[key: string]: string} {
    if(url.indexOf('?') !== -1) {
        return parseQueryString(url.split('?')[1]);
    } else {
        return {};
    }
}

export function parseQueryString(query: string) : {[key: string]: string} {
    let params: {[key: string]: string} = {};
    for(let v of query.split('&')) {
        let [key, val=""] = v.split('=');
        params[decodeURIComponent(key)] = decodeURIComponent(val);
    }
    return params;
}

/**
 * Given a promise returns a promise, which never fails, and returns
 * either [result, null] on success or [null, error] on failure
 *
 * Allows to write code which looks like
 *
 *   let data, error; try { data = await X } catch (e) { error = e; }
 *
 * Shorter:
 *
 *   let [data, error] = await withError(X);
 */
export function withError<T>(promise: Promise<T>) : Promise<[T, null] | [null, Error]> {
    return new Promise((done) => {
        this.then((result: T) => done([result, null]));
        this.catch((error: Error) => done([null, error]));
    });
}