infinitaslearning · teunmooij · Dec 8, 2024 · Dec 8, 2024
diff --git a/README.md b/README.md
@@ -270,7 +270,7 @@ You can rename dependencies passed to a components start function by specifying
 const system = systemic()
   .add('config', initConfig())
   .add('mongo', initMongo())
-  .dependsOn({ component: 'config', destination: 'options' } as const);
+  .dependsOn({ component: 'config', destination: 'options' });
 ```
 
 If you want to inject a property or subdocument of the dependency thing you can also express this with a dependency mapping
@@ -279,11 +279,10 @@ If you want to inject a property or subdocument of the dependency thing you can
 const system = systemic()
   .add('config', initConfig())
   .add('mongo', initMongo())
-  .dependsOn({ component: 'config', source: 'mongo' } as const);
+  .dependsOn({ component: 'config', source: 'mongo' });
 ```
 
 Now `config.mongo` will be injected as `config` instead of the entire configuration object.
-Because of the way typescript narrowing of object properties works, mappings need to be added as constants. Otherwise `@ilpt/systemic-ts` is not able to validate the dependency.
 
 #### Scoped Dependencies
 

diff --git a/changelog.md b/changelog.md
@@ -1,6 +1,6 @@
 ### What's changed
 
-- No changelog has been added to this release
+- Remove the need for marking a mapping dependency `as const`
 
 ---
 

diff --git a/src/types/dependencies.ts b/src/types/dependencies.ts
@@ -68,7 +68,7 @@ type ValidateMappingDependency<
   TDependencies extends Record<string, unknown>,
   TMapping extends { component: string; destination: string; source?: string },
 > = IsDestinationOrSourceUnbound<TMapping> extends true
-  ? [DependencyValidationError<string, unknown, unknown>] // Dependency not created as constant
+  ? [DependencyValidationError<string, unknown, unknown>] // Dependency cannot be determined
   : [PropAt<TDependencies, DependencyDestinationOf<TMapping>>] extends [never]
     ? [] // Unexpected dependency
     : [Injected<TSystemic, TCurrent, TMapping>] extends [

diff --git a/src/types/systemic.ts b/src/types/systemic.ts
@@ -144,7 +144,7 @@ export type DependsOn<
    * When name and type of the dependencies match those available in the system, the dependency can be added by name.
    * When a dependency is named differently in the system or only part of a component is required as a dependency, a MappingDependsOnOption can be used.
    */
-  dependsOn: <TNames extends DependsOnOption<Omit<TSystemic, TCurrent>>[]>(
+  dependsOn: <const TNames extends DependsOnOption<Omit<TSystemic, TCurrent>>[]>(
     ...names: TNames
   ) => ValidateDependencies<TSystemic, TCurrent, TDependencies, TNames> extends [
     infer First extends DependencyValidationError<any, any, any>,
@@ -171,7 +171,7 @@ export type SystemicWithInvalidDependency<
 > = {
   [X in keyof Systemic<any>]: (
     error: string extends TError[0]
-      ? `Destination of a dependency for component "${TCurrent}" is unknown. Did you neglect to mark it 'as const'?`
+      ? `Destination of a dependency for component "${TCurrent}" is unknown.`
       : `Dependency "${TError[0]}" on component "${TCurrent}" is not of the required type`,
     expected: TError[1],
     actual: TError[2],
@@ -195,7 +195,7 @@ type SystemicBuildDefaultComponent<
    * When name and type of the dependencies match those available in the system, the dependency can be added by name.
    * When a dependency is named differently in the system or only part of a component is required as a dependency, a MappingDependsOnOption can be used.
    */
-  dependsOn: <TNames extends DependsOnOption<Omit<TSystemic, TCurrent>>[]>(
+  dependsOn: <const TNames extends DependsOnOption<Omit<TSystemic, TCurrent>>[]>(
     ...names: TNames
   ) => ValidateDependencies<TSystemic, TCurrent, EmptyObject, TNames> extends [
     infer First extends DependencyValidationError<any, any, any>,

diff --git a/test/systemic.spec.ts b/test/systemic.spec.ts
@@ -336,7 +336,7 @@ describe("systemic", () => {
     const system = systemic()
       .add("foo", foo)
       .add("bar", bar)
-      .dependsOn({ component: "foo", destination: "baz" } as const);
+      .dependsOn({ component: "foo", destination: "baz" });
 
     await system.start();
 
@@ -349,7 +349,7 @@ describe("systemic", () => {
     const system = systemic()
       .add("foo", foo)
       .add("bar", bar)
-      .dependsOn({ component: "foo", destination: "baz" } as const);
+      .dependsOn({ component: "foo", destination: "baz" });
     await system.start();
     expect(bar.state.dependencies).toEqual({ baz: "foo" });
   });
@@ -359,7 +359,7 @@ describe("systemic", () => {
     const system = systemic()
       .add("foo", foo)
       .add("bar")
-      .dependsOn({ component: "foo", destination: "baz" } as const);
+      .dependsOn({ component: "foo", destination: "baz" });
     const components = await system.start();
     expect(components).toEqual({ foo: "foo", bar: { baz: "foo" } });
   });
@@ -370,7 +370,7 @@ describe("systemic", () => {
     const system = systemic()
       .add("foo", foo)
       .add("bar", bar)
-      .dependsOn({ component: "foo", source: "qux" } as const);
+      .dependsOn({ component: "foo", source: "qux" });
     await system.start();
     expect(bar.state.dependencies).toEqual({ foo: "baz" });
   });
@@ -381,7 +381,7 @@ describe("systemic", () => {
     const system = systemic()
       .add("foo", foo, { scoped: true })
       .add("bar", bar)
-      .dependsOn({ component: "foo", source: "" } as const);
+      .dependsOn({ component: "foo", source: "" });
     await system.start();
     expect(bar.state.dependencies).toEqual({ foo: { qux: "baz" } });
   });

diff --git a/test/types/systemic.spec.ts b/test/types/systemic.spec.ts
@@ -292,7 +292,7 @@ describe("systemic types", () => {
     const system = mockSystemic()
       .add("foo.bar", { start: async (deps: EmptyObject) => ({ baz: 42 }) })
       .add("qux", { start: async (deps: { baz: { baz: number } }) => 42 })
-      .dependsOn({ component: "foo.bar", destination: "baz" } as const);
+      .dependsOn({ component: "foo.bar", destination: "baz" });
 
     type Registrations = {
       "foo.bar": { component: { baz: number }; scoped: false };
@@ -307,7 +307,7 @@ describe("systemic types", () => {
     const system = mockSystemic()
       .add("foo", { start: async (deps: EmptyObject) => ({ baz: "qux" }) }, { scoped: true })
       .add("bar", { start: async (deps: { foo: { baz: string } }) => 42 })
-      .dependsOn({ component: "foo", source: "" } as const);
+      .dependsOn({ component: "foo", source: "" });
 
     type Registrations = {
       foo: { component: { baz: string }; scoped: true };
@@ -322,7 +322,7 @@ describe("systemic types", () => {
     const system = mockSystemic()
       .add("foo", { start: async (deps: EmptyObject) => ({ baz: "qux" }) }, { scoped: true })
       .add("bar", { start: async (deps: { foo: { baz: string } }) => 42 })
-      .dependsOn({ component: "foo", source: "test123" } as const);
+      .dependsOn({ component: "foo", source: "test123" });
 
     type Registrations = {
       foo: { component: { baz: string }; scoped: true };
@@ -333,44 +333,6 @@ describe("systemic types", () => {
     expectTypes<typeof system, Expected>().toBeEqual();
   });
 
-  it("is a systemic with a dependency not marked as const", () => {
-    const system = mockSystemic()
-      .add("foo", { start: async (deps: EmptyObject) => ({ bar: "bar" }) })
-      .add("bar", { start: async (deps: { baz: { bar: string } }) => 42 })
-      .dependsOn({ component: "foo", destination: "baz" });
-
-    type Expected = SystemicWithInvalidDependency<"bar", [string, unknown, unknown]>;
-
-    expectTypes<typeof system, Expected>().toBeEqual();
-    expectTypes<
-      (typeof system)["start"],
-      (
-        error: `Destination of a dependency for component "bar" is unknown. Did you neglect to mark it 'as const'?`,
-        expected: unknown,
-        actual: unknown,
-      ) => void
-    >().toBeEqual();
-  });
-
-  it("is a systemic with a dependency on a default component not marked as const", () => {
-    const system = mockSystemic()
-      .add("foo", { start: async (deps: EmptyObject) => ({ bar: "bar" }) })
-      .add("bar")
-      .dependsOn({ component: "foo", destination: "baz" });
-
-    type Expected = SystemicWithInvalidDependency<"bar", [string, unknown, unknown]>;
-
-    expectTypes<typeof system, Expected>().toBeEqual();
-    expectTypes<
-      (typeof system)["start"],
-      (
-        error: `Destination of a dependency for component "bar" is unknown. Did you neglect to mark it 'as const'?`,
-        expected: unknown,
-        actual: unknown,
-      ) => void
-    >().toBeEqual();
-  });
-
   it("is a systemic with an injected dependency that extends the expected type", () => {
     const system = mockSystemic()
       .add("foo", { start: async (deps: EmptyObject) => ({ foo: "bar" }) })