Typescript complaining about type on destructuring

Question

I have the following code:

import { GraphQLNonNull, GraphQLString, GraphQLList, GraphQLInt } from 'graphql';

import systemType from './type';
import { resolver } from 'graphql-sequelize';

let a = ({System}) => ({
  system: {
    type: systemType,
    args: {
      id: {
        description: 'ID of system',
        type: new GraphQLNonNull(GraphQLInt)
      }
    },
    resolve: resolver(System, {
      after: (result: any[]) => (result && result.length ? result[0] : result)
    })
  },
  systems: {
    type: new GraphQLList(systemType),
    args: {
      names: {
        description: 'List option names to retrieve',
        type: new GraphQLList(GraphQLString)
      },
      limit: {
        type: GraphQLInt
      },
      order: {
        type: GraphQLString
      }
    },
    resolve: resolver(System, {
      before: (findOptions: any, { query }: any) => ({
        order: [['name', 'DESC']],
        ...findOptions
      })
    })
  }
});

export = { a: a };

The VSCode is complaining with the TS7031 warning:

Binding element 'System' implicitly has an 'any' type

How can I get rid of that warning?

Answer 1

TypeScript cannot infer what type the System value should be from your code (or, more specifically, it cannot infer the type of first parameter to function a ). Just add an explicit type annotation to fix this:

let a = ({System}: { System: string }) => ({

});

Replace string with the actual type of System (perhaps typeof systemType ?)