Object to Querystring - JavaScript, JS, JSON

javascript-object-to-querystring.js

function objectToQuerystring (obj) {
  return Object.keys.reduce(function (str, key, i) {
    var delimiter, val;
    delimiter = (i === 0) ? '?' : '&';
    key = encodeURIComponent(key);
    val = encodeURIComponent(obj[key]);
    return [str, delimiter, key, '=', val].join('');
  }, '');
}

export const toQueryString = object =>
  '?' +
  Object.keys(object)
    .map(key => `${key}=${object[key].toString()}`)
    .join('&');

So handle recursive objects or arrays in the STANDARD query form a=val&b[0]=val&b[1]=val&c=val&d[some key]=val, here's the final function.

• It skips values for functions, null, undefined
• It skips keys and values for empty objects and arrays.
• It doesn't handle Number or String Objects made with new Number(1) or new String('my string') because NO ONE should ever do that

const objectToQueryString = (initialObj) => {
    const reducer = (obj, parentPrefix = null) => (prev, key) => {
      const val = obj[key];
      key = encodeURIComponent(key);
      const prefix = parentPrefix ? `${parentPrefix}[${key}]` : key;

      if (val == null || typeof val === 'function') {
        prev.push(`${prefix}=`);
        return prev;
      }

      if (['number', 'boolean', 'string'].includes(typeof val)) {
        prev.push(`${prefix}=${encodeURIComponent(val)}`);
        return prev;
      }

      prev.push(Object.keys(val).reduce(reducer(val, prefix), []).join('&'));
      return prev;
    };

    return Object.keys(initialObj).reduce(reducer(initialObj), []).join('&');
  };

  objectToQueryString({
    name: 'John Doe',
    age: 20,
    children: [
      { name: 'Foo Doe' },
      { name: 'Bar Doe' }
    ],
    wife: {
      name: 'Jane Doe'
    }
  });
  // -> name=John%20Doe&age=20&children[0][name]=Foo%20Doe&children[1][name]=Bar%20Doe&wife[name]=Jane%20Doe

const objectToQueryParams = (o = {}) => Object.entries(o) .map((p) => `${encodeURIComponent(p[0])}=${encodeURIComponent(p[1])}`) .join("&");

Refer below gist for more:
https://gist.github.com/bhaireshm

i created a gist for to recursively encode and decode querystrings (encode = object to querystring, decode = querystring to object).
Feel free to copy/paste this in your own projects.

Thanks @darkylmnx (his answer) for your encode function. I added the corresponding decode function (both in typescript format).
I tested the code by creating an complex object, encoding it to a querystring and decoding it to an object, then i compared the input object with the decoded output object.

Great 🔥 💯

const objectToQuerystring = obj => new URLSearchParams(obj).toString();

lol

const objectToQuerystring = obj => new URLSearchParams(obj).toString();

lol

That doesn't work with objects that contain arrays or other objects.