index.js
function getKeys(container) {
  function arrayIndex(value, i) {
    return i;
  }
  if (typeof container === 'object') {
    return Array.isArray(container) ? container.map(arrayIndex) : Object.keys(container);
  } else {
    return [];
  }
}
function getKeys(container) {
  function arrayIndex(value, i) {
    return i;
  }
  if (typeof container === 'object') {
    return Array.isArray(container) ? container.map(arrayIndex) : Object.keys(container);
  } else {
    return [];
  }
}
function getKeys ( container ) { function arrayIndex ( value , i ) { return i ; } if ( typeof container === 'object' ) { return Array . isArray ( container ) ? container . map ( arrayIndex ) : Object . keys ( container ) ; } else { return [ ] ; } }
Get the keys of an object as strings or those of an array as integers.
@param {object|Array} container A hash or array
@returns {Array.<string|number>} The keys of the container
Get the keys of an object as strings or those of an array as integers .