convert an object to a query string

query-params.js

import R from 'ramda';

const insertAmps = R.join('&');
const insertEquals = R.map(R.join('='));
const makeKeys = R.curry((f, pairs) => {
  const makeKeys_ = pair => [f(pair[0]), pair[1]];
  return R.map(makeKeys_, pairs);
});
const encodePairs = pairs => {
  const encodeAll = R.map(encodeURIComponent);
  return R.map(encodeAll, pairs);
};
const isPresent = val => !R.isNil(val) && !R.isEmpty(val);
const sndIsPresent = R.pipe(R.prop(1), isPresent);
const filterPresentValues = R.map(sndIsPresent);

const toQueryImpl = R.curry((f, obj) => {
  const fn = R.pipe(
    R.toPairs,
    filterPresentValues,
    encodePairs,
    makeKeys(f),
    insertEquals,
    insertAmps,
  );
  return fn(f, obj);
});

export const toQuery = toQueryImpl(R.identity);
export const mapKeysToQuery = toQueryImpl;

/* Example usage:
 * 
 * const query = { param1: 'foo', param2: 'bar', param3: '' }
 * import { mapKeysToQuery } from 'query-params';
 * mapKeysToQuery((k) => `asset_filter[${k}]`, query);
 */