Creates an arbitrary filter object, based on filter options, to notify when the state changes (logs).
To check if the state has changed, call eth_getFilterChanges.
note
Filters expire after 5 minutes of inactivity (no queries).
Note on specifying topic filters
[] “anything”[A] “A in first position (and anything after)”[null, B] “anything in first position AND B in second position (and anything after)”[A, B] “A in first position AND B in second position (and anything after)”[[A, B], [A, B]] “(A OR B) in first position AND (A OR B) in second position (and anything after)”Parameters
Object - An object of type Filter
fromBlock: QUANTITY|TAG - (optional, default “latest”) Integer block number,
or “earliest”, “latest” or “pending” for not yet mined transactionstoBlock: QUANTITY|TAG - (optional, default “latest”) Integer block number,
or “earliest”, “latest” or “pending” for not yet mined transactionsaddress: DATA|Array of DATA, 20 Bytes - (optional) Contract address or a list of addresses
from which logs should originatetopics: Array of DATA, - (optional) Array of 32 Bytes DATA topics. Topics are order-dependent.
Each topic can also be an array of DATA with “or” optionsReturns
QUANTITY - A filter id"demo"