Changing UpdateData<T> to expand support for types with index signatures. (#7318)

Changing UpdateData<T> to expand support for types with index signatures.

Author: MarkDuckworth

.changeset/breezy-flies-exist.md

@@ -0,0 +1,5 @@
+---
+"@firebase/firestore": minor
+---
+
+Changing UpdateData<T> to expand support for types with index signatures.

common/api-review/firestore-lite.api.md

@@ -14,7 +14,7 @@ export function addDoc<AppModelType, DbModelType extends DocumentData>(reference
 
 // @public
 export type AddPrefixToKeys<Prefix extends string, T extends Record<string, unknown>> = {
-    [K in keyof T & string as `${Prefix}.${K}`]+?: T[K];
+    [K in keyof T & string as `${Prefix}.${K}`]+?: string extends K ? any : T[K];
 };
 
 // @public

common/api-review/firestore.api.md

@@ -14,7 +14,7 @@ export function addDoc<AppModelType, DbModelType extends DocumentData>(reference
 
 // @public
 export type AddPrefixToKeys<Prefix extends string, T extends Record<string, unknown>> = {
-    [K in keyof T & string as `${Prefix}.${K}`]+?: T[K];
+    [K in keyof T & string as `${Prefix}.${K}`]+?: string extends K ? any : T[K];
 };
 
 // @public

docs-devsite/firestore_.md

@@ -2209,7 +2209,7 @@ Returns a new map where every key is prefixed with the outer key appended to a d
 
 ```typescript
 export declare type AddPrefixToKeys<Prefix extends string, T extends Record<string, unknown>> = {
-    [K in keyof T & string as `${Prefix}.${K}`]+?: T[K];
+    [K in keyof T & string as `${Prefix}.${K}`]+?: string extends K ? any : T[K];
 };
 ```
 

docs-devsite/firestore_lite.md

@@ -1424,7 +1424,7 @@ Returns a new map where every key is prefixed with the outer key appended to a d
 
 ```typescript
 export declare type AddPrefixToKeys<Prefix extends string, T extends Record<string, unknown>> = {
-    [K in keyof T & string as `${Prefix}.${K}`]+?: T[K];
+    [K in keyof T & string as `${Prefix}.${K}`]+?: string extends K ? any : T[K];
 };
 ```
 

packages/firestore/src/lite-api/types.ts

@@ -66,7 +66,22 @@ export type AddPrefixToKeys<
   T extends Record<string, unknown>
 > =
   // Remap K => Prefix.K. See https://www.typescriptlang.org/docs/handbook/2/mapped-types.html#key-remapping-via-as
-  { [K in keyof T & string as `${Prefix}.${K}`]+?: T[K] };
+
+  // `string extends K : ...` is used to detect index signatures
+  // like `{[key: string]: bool}`. We map these properties to type `any`
+  // because a field path like `foo.[string]` will match `foo.bar` or a
+  // sub-path `foo.bar.baz`. Because it matches a sub-path, we have to
+  // make this type `any` to allow for any types of the sub-path property.
+  // This is a significant downside to using index signatures in types for `T`
+  // for `UpdateData<T>`.
+
+  {
+    /* eslint-disable @typescript-eslint/no-explicit-any */
+    [K in keyof T & string as `${Prefix}.${K}`]+?: string extends K
+      ? any
+      : T[K];
+    /* eslint-enable @typescript-eslint/no-explicit-any */
+  };
 
 /**
  * Given a union type `U = T1 | T2 | ...`, returns an intersected type

packages/firestore/test/unit/lite-api/types.test.ts

@@ -441,23 +441,101 @@ describe('UpdateData - v9', () => {
         }
       };
 
-      // preserves type - failure
-      _ = {
-        // @ts-expect-error
-        'indexed.bar': false,
-        // @ts-expect-error
-        'indexed.baz': 'string'
+      expect(true).to.be.true;
+    });
+  });
+
+  // v10 tests cover new scenarios that are fixed for v10
+  describe('UpdateData - v10', () => {
+    interface MyV10ServerType {
+      booleanProperty: boolean;
+
+      // index signatures nested 1 layer deep
+      indexed: {
+        [name: string]: {
+          booleanProperty: boolean;
+          numberProperty: number;
+        };
       };
 
-      // preserves properties of nested objects - failure
-      _ = {
-        'indexed.bar': {
-          // @ts-expect-error
-          booleanProperty: 'string'
-        }
+      // index signatures nested 2 layers deep
+      layer: {
+        indexed: {
+          [name: string]: {
+            booleanProperty: boolean;
+            numberProperty: number;
+          };
+        };
       };
+    }
 
-      expect(true).to.be.true;
+    describe('given nested objects with index properties', () => {
+      it('supports object replacement at each layer (with partial)', () => {
+        // This unexpectidly fails in v9 when the object has index signature nested
+        // two layers deep (e.g. layer.indexed.[name]).
+        const _: UpdateData<MyV10ServerType> = {
+          indexed: {
+            bar: {},
+            baz: {}
+          }
+        };
+
+        expect(true).to.be.true;
+      });
+
+      it('allows dot notation for nested index types', () => {
+        let _: UpdateData<MyV10ServerType>;
+
+        // v10 allows 3 layers of dot notation
+
+        // allows the property
+        _ = {
+          'indexed.bar.booleanProperty': true
+        };
+
+        _ = {
+          'indexed.bar.numberProperty': 1
+        };
+
+        // does not enforce type
+        _ = {
+          'indexed.bar.booleanProperty': 'string value is not rejected'
+        };
+
+        _ = {
+          'indexed.bar.numberProperty': 'string value is not rejected'
+        };
+
+        // rejects properties that don't exist
+        _ = {
+          'indexed.bar.unknown': 'string value is not rejected'
+        };
+
+        expect(true).to.be.true;
+      });
+
+      it('allows dot notation for nested index types that are 2 layers deep', () => {
+        let _: UpdateData<MyV10ServerType>;
+
+        // v10 3 layers with dot notation
+
+        // allows the property
+        _ = {
+          'layer.indexed.bar.booleanProperty': true
+        };
+
+        // allows the property, but does not enforce type
+        _ = {
+          'layer.indexed.bar.booleanProperty': 'string value is not rejected'
+        };
+
+        // Allows unknown properties in sub types
+        _ = {
+          'layer.indexed.bar.unknownProperty': 'This just allows anything'
+        };
+
+        expect(true).to.be.true;
+      });
     });
   });
 });