Different item types can be reacted to. The item returned has a type property, the
other properties depend on the type of item. The possible types are:
message: the item will have a message property containing a message object and a channel property containing the channel ID for the message.
file: this item will have a file property containing a file object.
file_comment: the item will have a file property containing the file object and a comment property containing the file comment.
The users array in the reactions property might not always contain all users that have reacted (we limit it to X users, and X might change), however count will always represent the count of all
users who made that reaction (i.e. it may be greater than users.length). If the authenticated user has a given reaction then they are guaranteed to appear in the users array, regardless of
whether count is greater than users.length or not. If the complete list of users is required they can still be obtained by specifying the full argument.
This table lists the expected errors that this method could return.
However, other errors can be returned in the case where the service is down
or other unexpected factors affect processing. Callers should always
check the value of the ok params in the response.
Value passed for timestamp was invalid.
File specified by file does not exist.
File comment specified by file_comment does not exist.
Message specified by channel and timestamp does not exist.
file, file_comment, or combination of channel and timestamp was not specified.
No authentication token provided.
Invalid authentication token.
Authentication token is for a deleted user or team.
The method was passed an argument whose name falls outside the bounds of common decency. This includes very long names and names with non-alphanumeric characters other than _. If you get this error, it is typically an indication that you have made a very malformed API call.
The method was passed a PHP-style array argument (e.g. with a name like foo). These are never valid with the Slack API.
The method was called via a POST request, but the charset specified in the Content-Type header was invalid. Valid charset names are: utf-8iso-8859-1.
The method was called via a POST request with Content-Typeapplication/x-www-form-urlencoded or multipart/form-data, but the form data was either missing or syntactically invalid.
The method was called via a POST request, but the specified Content-Type was invalid. Valid types are: application/x-www-form-urlencodedmultipart/form-datatext/plain.
The method was called via a POST request and included a data payload, but the request did not include a Content-Type header.
The method was called via a POST request, but the POST data was either missing or truncated.
This table lists the expected warnings that this method will return.
However, other warnings can be returned in the case where the service
is experiencing unexpected trouble.
The method was called via a POST request, and recommended practice for the specified Content-Type is to include a charset parameter. However, no charset was present. Specifically, non-form-data content types (e.g. text/plain) are the ones for which charset is recommended.
The method was called via a POST request, and the specified Content-Type is not defined to understand the charset parameter. However, charset was in fact present. Specifically, form-data content types (e.g. multipart/form-data) are the ones for which charset is superfluous.