What is the purpose of appending ! after String param in graphql methods.
query method($param: String!)
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3Does this answer your question? [What is an exclamation point in GraphQL?](https://stackoverflow.com/questions/50684231/what-is-an-exclamation-point-in-graphql) – Malte Köhrer Oct 23 '20 at 12:18
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This modifier means that the type cannot be null.
String! means that the field is non-nullable, meaning that the GraphQL service promises to always give you a value when you query this field. In the type language, we'll represent those with an exclamation mark
The Non-Null type modifier can also be used when defining arguments for a field, which will cause the GraphQL server to return a validation error if a null value is passed as that argument, whether in the GraphQL string or in the variables.
David
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