I am trying to implement GraphQL but always get the error of Expected iterable. As I understand there can be an error with the types, but i tried everything and don't know what to do

that's what my API returns

        {
      "data": [
        {
          "id": "bitcoin",
          "rank": "1",
          "symbol": "BTC",
          "name": "Bitcoin",
          "supply": "17193925.0000000000000000",
          "maxSupply": "21000000.0000000000000000",
          "marketCapUsd": "119150835874.4699281625807300",
          "volumeUsd24Hr": "2927959461.1750323310959460",
          "priceUsd": "6929.8217756835584756",
          "changePercent24Hr": "-0.8101417214350335",
          "vwap24Hr": "7175.0663247679233209"
        },
     ......
]
}

and here is my code

  const coinType = new GraphQLObjectType({
  name: 'Coin',
  fields: () => ({
    id: { type: GraphQLString },
    name: { type: GraphQLString },
  })
});

// Root Query
const RootQuery = new GraphQLObjectType({
  name: 'RootQueryType',
  fields: () => ({

    coin: {
      type: new GraphQLList(launchType),
      resolve(parent, args) {
        return axios
          .get('https://api.coincap.io/v2/assets')
          .then(res => res.data);
      }
    },
  })
});

module.exports = new GraphQLSchema({
  query: RootQuery
});