Updating cached data from multiple parameterized queries after a mutation (hacky solution)

example.ts

addTask({
  variables: { input },
  optimisticResponse: {
    addTask: {
      __typename: 'Task',
      id,
      ...input
    }
  },
  update: (proxy: any, { data: { addTask } }: any) => {
    const query = Queries.tasks
    const variablesList = getVariablesListFromCache(proxy, query)

    for (const variables of variablesList) {
      const data = proxy.readQuery({ query, variables })
      data.tasks.push(addTask)
      proxy.writeQuery({ query, data })
    }
  }
})

getVariablesListFromCache.ts

const getVariablesListFromCache = (proxy: any, query: any) => {
  const queryName = query.definitions[0].name.value
  const rootQuery = proxy.data.data.ROOT_QUERY

  // XXX: When using `optimisticResponse`, `proxy.data.data` resolves to
  // another cache that doesn't contain the root query.
  if (!rootQuery) return []

  const matchQueryReducer = (names: string[], name: string) => {
    if (name.startsWith(queryName)) {
      names.push(name)
    }
    return names
  }

  const parseQueryNameToVariables = (name: string) =>
    JSON.parse((name.match(/{.*}/) as string[])[0])

  return Object.keys(rootQuery)
    .reduce(matchQueryReducer, [])
    .map(parseQueryNameToVariables)
}

In this case I need to match customers which is in the cache, but your code will match multiCustomersQuery.

@eric-burel I've felt this exact same thing, for me the solution that works best would be to use:

const queryName = query.definitions[0].selectionSet.selections[0].name.value

Instead of:

const queryName = query.definitions[0].name.value

Even with this, it would not handle queries that contains multiple subqueries below it:

query multiCustomersQuery {
    customers {
    }
    anotherThing {
    }
}

For my use case there are no such cases, so I do not need to worry, but it is good to warn about it.

In case it helps someone, I used the selectionSet since I use different names than the declared in the resolvers for the queries in the frontend. To avoid updating queries that are not the ones that I want I ended up using a simple regex, for example, if the query is lead, but I also have leads, I only want lead. This works for me:

const getVariablesListFromCache = (proxy: any, query: any) => {
    const queryName =
      query.definitions[0].selectionSet.selections[0].name.value;
    const rootQuery = proxy.data.data.ROOT_QUERY;

    if (!rootQuery) return [];

    const matchQueryReducer = (names: string[], name: string) => {
      const regex = new RegExp(`${queryName}\\(.*`);

      if (regex.test(name)) {
        names.push(name);
      }
      return names;
    };

    const parseQueryNameToVariables = (name: string) =>
      JSON.parse((name.match(/{.*}/) as string[])[0]);

    return Object.keys(rootQuery)
      .reduce(matchQueryReducer, [])
      .map(parseQueryNameToVariables);
  };