Relay uses initial variable during setVariables transition, not "last" variable - relayjs

Question

I have a page where a bunch of file ids get loaded from localStorage, then when the component mounts / receives new props, it calls setVariables. While this works and the new variables are set, the results from the initial variables is used during the transition, which causes an odd flickering result.
Why would Relay give me something different during the transition at all? My expectation would be that this.props.viewer.files.hits would be the same as the previous call while setVariables is doing its thing, not the result from using the initial variables.
const enhance = compose(
lifecycle({
componentDidMount() {
const { files, relay } = this.props
if (files.length) {
relay.setVariables(getCartFilterVariables(files))
}
},
}),
shouldUpdate((props, nextProps) => {
if (props.files.length !== nextProps.files.length && nextProps.files.length) {
props.relay.setVariables(getCartFilterVariables(nextProps.files))
}
return true
})
)
export { CartPage }
export default Relay.createContainer(
connect(state => state.cart)(enhance(CartPage)), {
initialVariables: {
first: 20,
offset: 0,
filters: {},
getFiles: false,
sort: '',
},
fragments: {
viewer: () => Relay.QL`
fragment on Root {
summary {
aggregations(filters: $filters) {
project__project_id {
buckets {
case_count
doc_count
file_size
key
}
}
fs { value }
}
}
files {
hits(first: $first, offset: $offset, filters: $filters, sort: $sort) {
${FileTable.getFragment('hits')}
}
}
}
`,
},
}
)

Answer 1

Ah I finally figured this out. prepareParams was changing the value
export const prepareViewerParams = (params, { location: { query } }) => ({
offset: parseIntParam(query.offset, 0),
first: parseIntParam(query.first, 20),
filters: parseJsonParam(query.filters, null), <-- setting filters variable
sort: query.sort || '',
})
const CartRoute = h(Route, {
path: '/cart',
component: CartPage,
prepareParams: prepareViewerParams, <--updating variable
queries: viewerQuery,
})