Javascript implementation of JQuery.param() $.param

encode-uri-object.js

function encodeURIObject = (obj, branch=[], results=[]) => {
    if (obj instanceof Object) {
        Object.keys(obj).forEach(key => {
            const newBranch = new Array(...branch);
            newBranch.push(key);
            encodeURIObject(obj[key], newBranch, results);
        });
        return results.join('&');
    }

    if (branch.length>0){
        results.push(`${encodeURIComponent(branch[0])}${branch.slice(1).map(el => encodeURIComponent(`[${el}]`)).join('')}=${encodeURIComponent(obj)}`);
    } else if (typeof(obj) === 'string') {
        return obj.split('').map((c,idx) => `${idx}=${encodeURIComponent(c)}`).join('&');
    } else {
        return '';
    }
};

// Usage
encodeURIObject({
    a: 'test',
    b: 'éàâ',
    c: [1,2,3,4],
    d: {e:1,f:2}
});
// returns
// a=test&b=%C3%A9%C3%A0%C3%A2&c%5B0%5D=1&c%5B1%5D=2&c%5B2%5D=3&c%5B3%5D=4&d%5Be%5D=1&d%5Bf%5D=2
// after decodeURIComponent 
// a=test&b=éàâ&c[0]=1&c[1]=2&c[2]=3&c[3]=4&d[e]=1&d[f]=2