support aliased fragments

CHANGELOG.md

@@ -6,6 +6,8 @@
 
 # Unreleased
 
+- Support `@alias` fragments.
+
 # 3.0.0-rc.9
 
 - Fix client extension enums mixup with `FutureAddedValue`.

packages/rescript-relay/__tests__/Test_aliasedFragments-tests.js

@@ -0,0 +1,27 @@
+require("@testing-library/jest-dom/extend-expect");
+const t = require("@testing-library/react");
+const React = require("react");
+const queryMock = require("./queryMock");
+
+const { test_aliasedFragments } = require("./Test_aliasedFragments.bs");
+
+describe("Aliased fragments", () => {
+  test("basic fragments work", async () => {
+    queryMock.mockQuery({
+      name: "TestAliasedFragmentsQuery",
+      variables: {
+        skipThing: false,
+      },
+      data: {
+        loggedInUser: {
+          id: "user-1",
+          firstName: "First",
+          lastName: "Last",
+        },
+      },
+    });
+
+    t.render(test_aliasedFragments());
+    await t.screen.findByText("First Last");
+  });
+});

packages/rescript-relay/__tests__/Test_aliasedFragments.res

@@ -0,0 +1,58 @@
+module FragmentFirstName = %relay(`
+  fragment TestAliasedFragments_userFirstName on User {
+    firstName
+  }
+`)
+
+module FragmentLastName = %relay(`
+  fragment TestAliasedFragments_userLastName on User {
+    lastName
+  }
+`)
+
+module Query = %relay(`
+    query TestAliasedFragmentsQuery($skipThing: Boolean!) {
+      loggedInUser {
+        ...TestAliasedFragments_userFirstName @alias
+        ...TestAliasedFragments_userLastName @alias @skip(if: $skipThing)
+      }
+    }
+`)
+
+module Test = {
+  @react.component
+  let make = () => {
+    let query = Query.use(~variables={skipThing: false})
+    let firstNameData = FragmentFirstName.use(
+      query.loggedInUser.testAliasedFragments_userFirstName.fragmentRefs,
+    )
+    let lastNameData = FragmentLastName.useOpt(
+      query.loggedInUser.testAliasedFragments_userLastName->Belt.Option.map(f => f.fragmentRefs),
+    )
+
+    <div>
+      {React.string(
+        firstNameData.firstName ++
+        " " ++
+        switch lastNameData {
+        | None => "-"
+        | Some({lastName}) => lastName
+        },
+      )}
+    </div>
+  }
+}
+
+@live
+let test_aliasedFragments = () => {
+  let network = RescriptRelay.Network.makePromiseBased(~fetchFunction=RelayEnv.fetchQuery)
+
+  let environment = RescriptRelay.Environment.make(
+    ~network,
+    ~store=RescriptRelay.Store.make(~source=RescriptRelay.RecordSource.make()),
+  )
+
+  <TestProviders.Wrapper environment>
+    <Test />
+  </TestProviders.Wrapper>
+}