fix TypeScript error when multiple clients are used

[azulite]

Hello,

I am working on a project with Vue and Typescript. When I try to define multiple endpoints with below code:

const apolloProvider = new VueApollo({
    clients: {
      dev: endpoint1,
      t2: endpoint2,
    },
    defaultClient: endpoint1,
  })

There has TypeScript error that is described at below:

TS2345: Argument of type '{ clients: { dev: ApolloClient<NormalizedCacheObject>; t2: ApolloClient<NormalizedCacheObject>; }...' is not assignable to parameter of type '{ de
faultClient: ApolloClient<{}>; defaultOptions?: VueApolloOptions | undefined; }'.
  Object literal may only specify known properties, and 'clients' does not exist in type '{ defaultClient: ApolloClient<{}>; defaultOptions?: VueApolloOptions | undefined; }'.

[joe-re]

@azulite
thanks! this is my mistake 🙇
Client property is optional value, so could you change it to type of optional value?
https://www.typescriptlang.org/docs/handbook/functions.html#optional-and-default-parameters

And I'm glad to run yarn run test:types on your local machine.(Your changes cause to fail tests...)

[joe-re]

I think it is better to use ApolloClient<{}>[] instead of any.

[azulite]

Ahhh yes I should run test and thank you for your suggestions! I am getting myself familiar with TypeScript still, your TS file saved my day 👏

[joe-re]

@azulite
Cool! It looks good to me.

@Akryum
Could you check it?