How do you call a mutation in GraphQL?
To call a mutation, you must use the keyword mutation before your GraphQL query. To pass an input type, provide the data written as if it’s a JSON object. To pass an input type, provide the data written as if it’s a JSON object.
Is the GraphQL server able to handle errors?
GraphQL servers are able to handle errors by default, both for syntax and validations errors. You’ve probably already seen this when using GraphiQLor any other playground to explore GraphQL APIs. But often the default way is not sufficient for more complex situations or to sophistically handle the errors from a frontend application.
How to extend the error object in GraphQL?
Fortunately, the GraphQL specification allows you to add a field called extensions to the error object. To extend the error object, you can either throw a custom Error object or use predefined error methods available in Apollo Server.
How to pass an input type in GraphQL?
To pass an input type, provide the data written as if it’s a JSON object. For example, with the server defined above, you can create a new message and return the id of the new message with this operation:
How to add new student record using mutation query?
Let us understand how to add new student record into the datastore using a mutation query. Create a project folder by the name mutation-app. Change your directory to mutation-app from the terminal. Follow steps 3 to 5 explained in the Environment Setup chapter. Add schema.graphql file in the project folder mutation-app and add the following code −
Can you pass more than one argument in GraphQL?
In a system like REST, you can only pass a single set of arguments – the query parameters and URL segments in your request. But in GraphQL, every field and nested object can get its own set of arguments, making GraphQL a complete replacement for making multiple API fetches.
What does the usemutation hook do in GraphQL?
The useMutation hook accepts the following options: A GraphQL mutation document parsed into an AST by graphql-tag. Optional for the useMutation Hook since the mutation can be passed in as the first parameter to the Hook. Required for the Mutation component.
Can a GraphQL document be parsed into an AST?
A GraphQL mutation document parsed into an AST by graphql-tag. Optional for the useMutation Hook since the mutation can be passed in as the first parameter to the Hook. Required for the Mutation component. If true, the returned data property will not update with the mutation result.