AWS Amplify GraphQL Operations with TypeScript and Hooks - Part 3 [Mutations]

Let's take a quick look at mutations. This will be a short post, as Amplify makes mutations relatively painless, and the format of GraphQL mutations that we'll look at closely resemble the queries that we've already looked at (take a look at the previous posts in this series for more on that).

Mutations

To set up for mutations, we need to look at part of the query we did in the previous section.

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const fetchQuery = async (query: string, variables?: VariablesType) => {
  try {
    setLoading(true)
    const { data } = (await API.graphql(
      graphqlOperation(query, variables),
    )) as {
      data: ResultType
    }
    setData(data)
  } catch (error) {
    console.log(error)
    setError(error)
  } finally {
    setLoading(false)
  }
}

All GraphQL API calls made with Amplify using the graphqlOperation function. We can reuse this, so let's make another function to handle the returning of data.

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export const gqlOp = async <
  ResultType extends {},
  VariablesType extends {} = {}
>(
  query: string,
  variables?: VariablesType,
) => {
  const { data } = (await API.graphql(graphqlOperation(query, variables))) as {
    data: ResultType
  }
  return data
}

Now we can use this little function in place of the fetch call.

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const fetchQuery = async (query: string, variables?: VariablesType) => {
  try {
    setLoading(true)
    const data = await gqlOp<ResultType, VariablesType>(query, variables)
    setData(data)
  } catch (error) {
    console.log(error)
    setError(error)
  } finally {
    setLoading(false)
  }
}

Now that's done, let's create a function for mutations.

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export const mutation = async <
  ResultType extends {},
  VariablesType extends {} = {}
>(
  query: string,
  variables?: VariablesType,
) => gqlOp<ResultType, VariablesType>(query, variables)

Alright, that's it. Thanks for reading!

Stay tuned for the next one where we tackle subscriptions.