Refactor code

[ya7on]

We need to fix some places in our code.

• toString method we are used for strings. It is overcode. We need to remove it.
  msg.message.user.name is already string. We do not need to convert it to string.
  
• We use let operator for names that we are not been changing. The good solution would be replace it to const operator.
  For example this place. We assign these names only one time. It is redundant to keep their values in variables.