simplify context type (#66)

Allow for near-infinite deep dependency trees.

Co-authored-by: Nico Jansen <jansennico@gmail.com>

Author: mayorandrew

src/api/TChildContext.ts

@@ -1,13 +1,14 @@
+// Forces typescript to explicitly calculate the complicated type
+export type Simplify<T> = {} & { [K in keyof T]: T[K] };
+
 export type TChildContext<
   TParentContext,
   TProvided,
   CurrentToken extends string,
-> = {
-  [K in keyof (TParentContext & {
-    [K in CurrentToken]: TProvided;
-  })]: K extends CurrentToken
+> = Simplify<{
+  [K in keyof TParentContext | CurrentToken]: K extends CurrentToken //
     ? TProvided
     : K extends keyof TParentContext
       ? TParentContext[K]
       : never;
-};
+}>;

testResources/long-dependency-graph.ts

@@ -0,0 +1,54 @@
+// error: false
+import { createInjector, tokens } from '../src/index.js';
+
+const rootInjector = createInjector();
+
+class Foo {
+  constructor(public qux: boolean) {}
+  public static inject = tokens('qux');
+}
+
+const fooInjector = rootInjector
+  .provideValue('qux', true)
+  .provideClass('foo1', Foo)
+  .provideClass('foo2', Foo)
+  .provideClass('foo3', Foo)
+  .provideClass('foo4', Foo)
+  .provideClass('foo5', Foo)
+  .provideClass('foo6', Foo)
+  .provideClass('foo7', Foo)
+  .provideClass('foo8', Foo)
+  .provideClass('foo9', Foo)
+  .provideClass('foo10', Foo)
+  .provideClass('foo11', Foo)
+  .provideClass('foo12', Foo)
+  .provideClass('foo13', Foo)
+  .provideClass('foo14', Foo)
+  .provideClass('foo15', Foo)
+  .provideClass('foo16', Foo)
+  .provideClass('foo17', Foo)
+  .provideClass('foo18', Foo)
+  .provideClass('foo19', Foo)
+  .provideClass('foo20', Foo)
+  .provideClass('foo21', Foo)
+  .provideClass('foo22', Foo)
+  .provideClass('foo23', Foo)
+  .provideClass('foo24', Foo)
+  .provideClass('foo25', Foo)
+  .provideClass('foo26', Foo)
+  .provideClass('foo27', Foo)
+  .provideClass('foo28', Foo)
+  .provideClass('foo29', Foo)
+  .provideClass('foo30', Foo)
+  .provideClass('foo41', Foo)
+  .provideClass('foo42', Foo)
+  .provideClass('foo43', Foo)
+  .provideClass('foo44', Foo)
+  .provideClass('foo45', Foo)
+  .provideClass('foo46', Foo)
+  .provideClass('foo47', Foo)
+  .provideClass('foo48', Foo)
+  .provideClass('foo49', Foo)
+  .provideClass('foo50', Foo);
+
+const foo = fooInjector.resolve('foo50');

testResources/tokens-of-type-string.ts

@@ -1,4 +1,4 @@
-// error: "Type 'string[]' is not assignable to type 'readonly InjectionToken<TChildContext<{}, number, \"bar\">>[]'"
+// error: "Type 'string[]' is not assignable to type 'readonly InjectionToken<{ bar: number; }>[]'"
 
 import { createInjector } from '../src/index.js';