# GOTTA LOVE SOME QUERIES --- # What is a directive ? --- - a directive is an instruction and in this case GraphQL has two main ones which are : - **@include** - which allows you to filter returned data - **@skip** - which allows you to omit data - they both work if a passed in value or condition is true. ---  --- # What are arguments ? --- - In many cases you will need to pass in arguments to your queries.  --- <!-- Ephie --> # How do we use fragments in queries? Why would we? <!-- Amber --> ---- ## What is a fragment ? fragment: a reusable part of a query 3 unique components: name, typename, body ``` fragment Name on TypeName { field1 field2 field3 } ``` ---- ## When to use a fragment ``` { googleRepo: repository (owner:"google", name:"WebFundamentals") { name owner { id, avatarUrl resourcePath url } } facebookRepo: repository (owner:"facebook", name:"react") { name owner { id, avatarUrl resourcePath url url } } ``` ---- ## How to create a fragment ``` fragment ownerInfo on RepositoryOwner { id avatarUrl resourcePath url } ``` ---- ## How to use a fragment ``` { googleRepo: repository(owner: "google", name: "WebFundamentals") { name owner { ...ownerInfo //fragment } } facebookRepo: repository(owner: "facebook", name: "react") { name owner { ...ownerInfo //fragment } } } ``` <!-- ---- ### Bonus: on fragments and caching --> --- ### What is an operation name <!-- aishah --> > Operation name ≈ Function name ``` query Skeleton{ bone(id: 3241) { name, location } } ``` <!-- Our choice --> --- ### Why use operation names - Best practice: use operation names and types - makes codebase less ambiguous - helps with debugging query in case of error - When we have more than one operation in a document - must be named otherwise error. ---  ---