function getExternalKeyNameLength (key) {
	  if (typeof key !== 'string') {
	    key = String(key);
	  }
	  var hashPos = key.indexOf('->');
	  return hashPos === -1 ? key.length : hashPos
	}
Get indexes of keys in the command arguments

@param {string} commandName - the command name
@param {string[]} args - the arguments of the command
@param {object} [options] - options
@param {boolean} [options.parseExternalKey] - parse external keys
@return {number[]} - the list of the index
@public

@example
```javascript
getKeyIndexes('set', ['key', 'value']) // [0]
getKeyIndexes('mget', ['key1', 'key2']) // [0, 1]
```