Merge a1a87b9 into e5c1382

index.d.ts

@@ -18,32 +18,32 @@ export declare type Spec<T, C extends CustomCommands<object> = never> = (T exten
     $apply: (v: T) => T;
 } | ((v: T) => T) | (C extends CustomCommands<infer O> ? O : never);
 declare type ArraySpec<T, C extends CustomCommands<object>> = {
-    $push: T[];
+    $push: ReadonlyArray<T>;
 } | {
-    $unshift: T[];
+    $unshift: ReadonlyArray<T>;
 } | {
-    $splice: Array<[number, number?] | [number, number, ...T[]]>;
+    $splice: ReadonlyArray<[number, number?] | [number, number, ...T[]]>;
 } | {
     [index: string]: Spec<T, C>;
 };
 declare type MapSpec<K, V> = {
-    $add: Array<[K, V]>;
+    $add: ReadonlyArray<[K, V]>;
 } | {
-    $remove: K[];
+    $remove: ReadonlyArray<K>;
 } | {
     [key: string]: {
         $set: V;
     };
 };
 declare type SetSpec<T> = {
-    $add: T[];
+    $add: ReadonlyArray<T>;
 } | {
-    $remove: T[];
+    $remove: ReadonlyArray<T>;
 };
 declare type ObjectSpec<T, C extends CustomCommands<object>> = {
-    $toggle: Array<keyof T>;
+    $toggle: ReadonlyArray<keyof T>;
 } | {
-    $unset: Array<keyof T>;
+    $unset: ReadonlyArray<keyof T>;
 } | {
     $merge: Partial<T>;
 } | {

index.ts

@@ -23,8 +23,8 @@ const getAllKeys = typeof Object.getOwnPropertySymbols === 'function'
   : obj => Object.keys(obj);
 
 function copy<T, U, K, V, X>(
-  object: T extends U[]
-    ? U[]
+  object: T extends ReadonlyArray<U>
+    ? ReadonlyArray<U>
     : T extends Map<K, V>
       ? Map<K, V>
       : T extends Set<X>
@@ -336,22 +336,22 @@ export type Spec<T, C extends CustomCommands<object> = never> =
   | (C extends CustomCommands<infer O> ? O : never);
 
 type ArraySpec<T, C extends CustomCommands<object>> =
-  | { $push: T[] }
-  | { $unshift: T[] }
-  | { $splice: Array<[number, number?] | [number, number, ...T[]]> }
+  | { $push: ReadonlyArray<T> }
+  | { $unshift: ReadonlyArray<T> }
+  | { $splice: ReadonlyArray<[number, number?] | [number, number, ...T[]]> }
   | { [index: string]: Spec<T, C> }; // Note that this does not type check properly if index: number.
 
 type MapSpec<K, V> =
-  | { $add: Array<[K, V]> }
-  | { $remove: K[] }
+  | { $add: ReadonlyArray<[K, V]> }
+  | { $remove: ReadonlyArray<K> }
   | { [key: string]: { $set: V } };
 
 type SetSpec<T> =
-  | { $add: T[] }
-  | { $remove: T[] };
+  | { $add: ReadonlyArray<T> }
+  | { $remove: ReadonlyArray<T> };
 
 type ObjectSpec<T, C extends CustomCommands<object>> =
-  | { $toggle: Array<keyof T> }
-  | { $unset: Array<keyof T> }
+  | { $toggle: ReadonlyArray<keyof T> }
+  | { $unset: ReadonlyArray<keyof T> }
   | { $merge: Partial<T> }
   | { [K in keyof T]?: Spec<T[K], C> };

test.ts

@@ -634,3 +634,25 @@ describe('update', () => {
     expect(typeof (update as any).newContext()).toBe('function');
   });
 });
+
+describe('works with readonly arrays', () => {
+  interface Thing {
+    bar: {
+      foo: ReadonlyArray<{ baz: number }>;
+    };
+  }
+
+  const a: Thing = {
+    bar: { foo: [ {baz: 1} ] }
+  };
+  const b: Thing = {
+    bar: { foo: [ {baz: 2} ] }
+  };
+  expect(update(a, {
+    bar: {
+      foo: { $push: b.bar.foo }
+    }
+  })).toEqual({
+    bar: { foo: [{ baz: 1 }, { baz: 2 }]}
+  });
+});