Upgrading setVariables

Examples on how to migrate this.props.setVariables calls from the old API.

this.props.setVariables from the old API does not have a direct equivalent in the new API. A big reason for this change is that the new core no longer tracks how to refetch any specific sub-tree from the query. This makes the new core a lot faster, but requires explicit queries for how to fetch new data. Check out these four different scenarios:

`initialVariables`

If the component doesn't actually use setVariables(), and just uses initialVariables to share values between JS and GraphQL, there are two alternative approaches:

Inline the value in the GraphQL query, potentially annotating with a GraphQL comment (i.e. # PAGE_SIZE).
Add the variable to the queries that use the fragment and pass it in when fetching the query. For this it can be useful to have a module with a collection of variables for your product.

Pagination

Typical Relay Classic code:

// counterexample
this.props.relay.setVariables({
  count: count + 10,
});

initialVariables: {
  count: 10,
},

fragment on User {
  friends(first: $count) {
    # ...
  }
}

This should be upgraded to use a PaginationContainer.

Changing Arguments

Typical old code:

// counterexample
this.props.relay.setVariables({
  search: newSearchTerm,
});

initialVariables: {
  search: '',
}

fragment on User {
  friends(named: $search, first: 10) {
    # ...
  }
}

This can be upgraded by using a RefetchContainer which allows you to specify the exact query to use to fetch the new data.

Show More

Typical old code:

// counterexample
this.props.relay.setVariables({
  showComments: true,
});

initialVariables: {
  showComments: false,
}

fragment on FeedbackTarget {
  comments(first: 10) @include(if: $showComments) {
    # ...
  }
}

This can be upgraded by conditionally rendering a QueryRenderer which will load the data once it is rendered. The code overhead of doing this is dramatically reduced with the new API.

Alternatively a RefetchContainer can also be used.