Field arguments

Many of fields in graphql queries use arguments. eg

query {
  calculator {
    add(a: 2, b: 3)
  }
}

Let's create such Calculator object type.

import { ObjectType, Field } from 'typegql';

@ObjectType()
class Calculator {
  @Field()
  add(a: number, b: number): number {
    return a + b;
  }
}

Note we didn't even have to use @Arg decorator yet. In case of simple, scalar argument types like string, number, boolean it's not required. By default arguments not decorated with @Arg are required.

Customizing argumens (eg. adding default value)

Let's say we're building another calculator metod, called pow which returns base to the exponent power (base^exponent). By default, we want exponent to be 2.

import { ObjectType, Field, Arg } from 'typegql';

@ObjectType()
class Calculator {
  @Field()
  pow(
    base: number,
    @Arg({ nullable: true, defaultValue: 2 })
    exponent: number,
  ): number {
    return Math.pow(base, exponent);
  }
}

Right now exponent argument is optional so we can use both:

framgnet A on Calculator {
  pow(2) # 4
}

framgnet B on Calculator {
  pow(2, 5) # 32
}