fix: Correctly handle ObjectTypeSpreadProperty in object type annotations (#593)

Co-authored-by: Daniel Tschinder <[email protected]>

Author: imdreamrunner

src/utils/__tests__/__snapshots__/getFlowType-test.js.snap

@@ -0,0 +1,107 @@
+// Jest Snapshot v1, https://goo.gl/fbAQLP
+
+exports[`getFlowType handles ObjectTypeSpreadProperty 1`] = `
+Object {
+  "name": "signature",
+  "raw": "{| apple: string, banana: string, ...OtherFruits |}",
+  "signature": Object {
+    "properties": Array [
+      Object {
+        "key": "apple",
+        "value": Object {
+          "name": "string",
+          "required": true,
+        },
+      },
+      Object {
+        "key": "banana",
+        "value": Object {
+          "name": "string",
+          "required": true,
+        },
+      },
+      Object {
+        "key": "orange",
+        "value": Object {
+          "name": "string",
+          "required": true,
+        },
+      },
+    ],
+  },
+  "type": "object",
+}
+`;
+
+exports[`getFlowType handles nested ObjectTypeSpreadProperty 1`] = `
+Object {
+  "name": "signature",
+  "raw": "{| apple: string, banana: string, ...BreakfastFruits |}",
+  "signature": Object {
+    "properties": Array [
+      Object {
+        "key": "apple",
+        "value": Object {
+          "name": "string",
+          "required": true,
+        },
+      },
+      Object {
+        "key": "banana",
+        "value": Object {
+          "name": "string",
+          "required": true,
+        },
+      },
+      Object {
+        "key": "mango",
+        "value": Object {
+          "name": "string",
+          "required": true,
+        },
+      },
+      Object {
+        "key": "orange",
+        "value": Object {
+          "name": "string",
+          "required": true,
+        },
+      },
+      Object {
+        "key": "lemon",
+        "value": Object {
+          "name": "string",
+          "required": true,
+        },
+      },
+    ],
+  },
+  "type": "object",
+}
+`;
+
+exports[`getFlowType handles unresolved ObjectTypeSpreadProperty 1`] = `
+Object {
+  "name": "signature",
+  "raw": "{| apple: string, banana: string, ...MyType |}",
+  "signature": Object {
+    "properties": Array [
+      Object {
+        "key": "apple",
+        "value": Object {
+          "name": "string",
+          "required": true,
+        },
+      },
+      Object {
+        "key": "banana",
+        "value": Object {
+          "name": "string",
+          "required": true,
+        },
+      },
+    ],
+  },
+  "type": "object",
+}
+`;

src/utils/__tests__/getFlowType-test.js

@@ -745,4 +745,43 @@ describe('getFlowType', () => {
       raw: '{ subAction: SubAction }',
     });
   });
+
+  it('handles ObjectTypeSpreadProperty', () => {
+    const typePath = statement(`
+      var x: {| apple: string, banana: string, ...OtherFruits |} = 2;
+      type OtherFruits = { orange: string }
+    `)
+      .get('declarations', 0)
+      .get('id')
+      .get('typeAnnotation')
+      .get('typeAnnotation');
+
+    expect(getFlowType(typePath)).toMatchSnapshot();
+  });
+
+  it('handles unresolved ObjectTypeSpreadProperty', () => {
+    const typePath = statement(`
+      var x: {| apple: string, banana: string, ...MyType |} = 2;
+    `)
+      .get('declarations', 0)
+      .get('id')
+      .get('typeAnnotation')
+      .get('typeAnnotation');
+
+    expect(getFlowType(typePath)).toMatchSnapshot();
+  });
+
+  it('handles nested ObjectTypeSpreadProperty', () => {
+    const typePath = statement(`
+      var x: {| apple: string, banana: string, ...BreakfastFruits |} = 2;
+      type BreakfastFruits = { mango: string, ...CitrusFruits };
+      type CitrusFruits = { orange: string, lemon: string };
+    `)
+      .get('declarations', 0)
+      .get('id')
+      .get('typeAnnotation')
+      .get('typeAnnotation');
+
+    expect(getFlowType(typePath)).toMatchSnapshot();
+  });
 });

src/utils/getFlowType.js

@@ -201,6 +201,18 @@ function handleObjectTypeAnnotation(
         key: ((getPropertyName(param): any): string),
         value: getFlowTypeWithRequirements(param.get('value'), typeParams),
       });
+    } else if (t.ObjectTypeSpreadProperty.check(param.node)) {
+      let spreadObject = resolveToValue(param.get('argument'));
+      if (t.GenericTypeAnnotation.check(spreadObject.node)) {
+        const typeAlias = resolveToValue(spreadObject.get('id'));
+        if (t.ObjectTypeAnnotation.check(typeAlias.get('right').node)) {
+          spreadObject = resolveToValue(typeAlias.get('right'));
+        }
+      }
+      if (t.ObjectTypeAnnotation.check(spreadObject.node)) {
+        const props = handleObjectTypeAnnotation(spreadObject, typeParams);
+        type.signature.properties.push(...props.signature.properties);
+      }
     }
   });