How to define and execute GraphQL query with filter -

so thing try is, retrieve filtered data database (mongodb in situation) using graphql.

speaking in "mysql language" how implement where clause in graphql?

i followed tutorial : https://learngraphql.com/basics/using-a-real-data-source/5

query filter defined :

const query = new graphqlobjecttype({   name: "queries",   fields: {     authors: {       type: new graphqllist(author),       resolve: function(rootvalue, args, info) {         let fields = {};         let fieldasts = info.fieldasts;         fieldasts[0].selectionset.selections.map(function(selection) {           fields[selection.name.value] = 1;         });         return db.authors.find({}, fields).toarray();       }     }   } }); 

the tricky part here info parameter in resolve function. explanations i've found here : http://pcarion.com/2015/09/26/graphql-resolve/

so ast (abstract syntax tree)

can please provide basic real-life example code show how define , execute following query : get authors name == john

thank you!

there no need examine ast. awfully laborious.

all need define argument on author field. second paramenter of resolver, can check arguement , include in mongo query.

const query = new graphqlobjecttype({   name: "queries",   fields: {     authors: {       type: new graphqllist(author),        // define arguments , types here       args: {         name: { type: graphqlstring }       },        resolve: function(rootvalue, args, info) {         let fields = {};         // , can check arguments' values         if (args.name) {           fields.name = args.name         }         // , use when constructing query         return db.authors.find(fields, fields).toarray();       }     }   } });