generate query params from object like URLSearchParams()

generateQueryParams.js

const generateQueryParams = (obj) => {
  if (typeof obj !== 'object') {
    return '';
  }
  const strs = [];
  Object.keys(obj).forEach((key) => {
    const k = encodeURIComponent(key);
    const item = obj[key];
    if (Array.isArray(item)) {
      item.forEach((i) => {
        const v = encodeURIComponent(i);
        strs.push(`${k}=${v}`);
      });
    } else if (typeof item === 'string' || typeof item === 'number') {
      const i = encodeURIComponent(item);
      strs.push(`${k}=${i}`);
    }
  });
  return strs.join('&');
};

The original intention was to solve the form of arrays in search params.
The final array here will be arr=1&arr=2&arr=3
Conforms to the way most Gateway frameworks parse arrays in search params.