Get Flat Object

flat-object.js

// Turns
{
  inputQueryId: 'gcd-input-query',
  cssClasses: {
    namespace: 'ol-geocoder',
    spin: 'gcd-pseudo-rotate'
    glass: {
      container: 'gcd-gl-container'
    }
}

// Into
{
  inputQueryId: 'gcd-input-query',
  cssClasses_namespace: 'ol-geocoder',
  cssClasses_spin: 'gcd-pseudo-rotate',
  cssClasses_glass_container: 'gcd-gl-container'
}

function getFlatVars(obj, prev = []) {
  return Object.keys(obj).reduce((acc, curr) => {
    if (typeof obj[curr] === 'object') {
      prev.push(curr);
      const flat = getFlatVars(obj[curr], prev);
      Object.keys(flat).forEach(k => { acc[k] = flat[k] });
    } else {
      if (prev.length) {
        acc[`${prev.join('_')}_${curr}`] = obj[curr];
      } else {
        acc[curr] = obj[curr];
      }
    }
    return acc;
  }, {});
}