August 2019
Intermediate to advanced
486 pages
13h 52m
English
Content preview from Mastering Blockchain Programming with Solidity
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Operator approvals kept in _operatorApprovals
An operator is a potential, trusted third party that can be added by an owner who owns one or more NFT tokens.
If an owner of one or more NFT tokens gives approval to an operator (another address), then the operator is allowed to withdraw any of the owner's tokens from the owner's address, and he is allowed to send it to another address or to themselves.
Just to simplify, an operator has approvals for all the NFT tokens present in the owner's account.
The mapping of a mapping is used to find the operator's addresses that are approved by a given owner's address:
mapping (address => mapping (address => bool)) private _operatorApprovals;function setApprovalForAll(address to, bool approved) public ...