fix: revert 2218 to fix ts excessively deep types (#2234)

Author: coolsoftwaretyler

__tests__/core/2230.test.ts

@@ -1,5 +1,4 @@
 //github.com/mobxjs/mobx-state-tree/issues/2230
-
 import { describe, test } from "bun:test"
 import { types, Instance } from "../../src/index"
 
@@ -150,6 +149,31 @@ describe("2230 - type instantiation is excessively deep and possibly infinite",
                 return self.prop41
             }
         }))
+            .actions((self: IAction4) => ({
+                getProp51(): string {
+                    return self.prop51
+                }
+            }))
+            .actions((self: IAction4) => ({
+                getProp61(): string {
+                    return self.prop61
+                }
+            }))
+            .actions((self: IAction4) => ({
+                getProp71(): string {
+                    return self.prop71
+                }
+            }))
+            .actions((self: IAction4) => ({
+                getProp81(): string {
+                    return self.prop81
+                }
+            }))
+            .actions((self: IAction4) => ({
+                getProp91(): string {
+                    return self.prop91
+                }
+            }))
         interface IAction5 extends Instance<typeof Action5> {}
     })
 })

__tests__/core/type-system.test.ts

@@ -1417,84 +1417,3 @@ test("#1627 - union dispatch function is typed", () => {
         types.null
     )
 })
-
-test("#2216 - should respect optionality when extending another type", () => {
-    const Base = types.model("ErrorStore", { value: types.string }).extend(self => ({
-        actions: {
-            setValue(value?: string): boolean {
-                self.value = value || "test"
-                return true
-            },
-
-            setAnotherValue(value?: string): boolean {
-                self.value = value || "test"
-                return true
-            }
-        },
-        views: {
-            get spam(): string {
-                return self.value
-            },
-
-            get eggs(): string {
-                return self.value
-            }
-        },
-        state: {
-            anotherValue: "test" as string,
-            soManyValues: "test" as string
-        }
-    }))
-
-    const Extended = Base.named("Extended")
-        .props({
-            value: "test"
-        })
-        .extend(self => ({
-            actions: {
-                setValue(value: string): number {
-                    self.value = value
-                    return value.length
-                }
-            },
-            views: {
-                get spam(): boolean {
-                    return !!self.value
-                }
-            },
-            state: {
-                anotherValue: "test" as string | undefined
-            }
-        }))
-        .actions(self => ({
-            setAnotherValue(value: string): number {
-                self.value = value
-                return value.length
-            }
-        }))
-        .views(self => ({
-            get eggs(): boolean {
-                return !!self.value
-            }
-        }))
-        .volatile(self => ({
-            soManyValues: "test" as string | undefined
-        }))
-
-    type InputSnapshot = SnapshotIn<typeof Extended>
-    type InstanceType = Instance<typeof Extended>
-
-    assertTypesEqual(_ as InputSnapshot, _ as { value?: string })
-    assertTypesEqual(
-        _ as InstanceType,
-        _ as {
-            value: string
-            setValue(value: string): number
-            setAnotherValue(value: string): number
-            spam: boolean
-            eggs: boolean
-            anotherValue: string | undefined
-            soManyValues: string | undefined
-        }
-    )
-})

src/types/complex-types/model.ts

@@ -73,11 +73,6 @@ export interface ModelPropertiesDeclaration {
     [key: string]: ModelPrimitive | IAnyType
 }
 
-/** intersect two object types, but omit keys of B from A before doing so */
-type OmitMerge<A, B> = {
-    [K in keyof A as K extends keyof B ? never : K]: A[K]
-} & B
-
 /**
  * Unmaps syntax property declarations to a map of { propName: IType }
  *
@@ -205,28 +200,23 @@ export interface IModelType<
     // so it is recommended to use pre/post process snapshot after all props have been defined
     props<PROPS2 extends ModelPropertiesDeclaration>(
         props: PROPS2
-    ): IModelType<
-        OmitMerge<PROPS, ModelPropertiesDeclarationToProperties<PROPS2>>,
-        OTHERS,
-        CustomC,
-        CustomS
-    >
+    ): IModelType<PROPS & ModelPropertiesDeclarationToProperties<PROPS2>, OTHERS, CustomC, CustomS>
 
-    views<V extends AnyObject>(
+    views<V extends Object>(
         fn: (self: Instance<this>) => V
-    ): IModelType<PROPS, OmitMerge<OTHERS, V>, CustomC, CustomS>
+    ): IModelType<PROPS, OTHERS & V, CustomC, CustomS>
 
     actions<A extends ModelActions>(
         fn: (self: Instance<this>) => A
-    ): IModelType<PROPS, OmitMerge<OTHERS, A>, CustomC, CustomS>
+    ): IModelType<PROPS, OTHERS & A, CustomC, CustomS>
 
-    volatile<VS extends AnyObject>(
-        fn: (self: Instance<this>) => VS
-    ): IModelType<PROPS, OmitMerge<OTHERS, VS>, CustomC, CustomS>
+    volatile<TP extends object>(
+        fn: (self: Instance<this>) => TP
+    ): IModelType<PROPS, OTHERS & TP, CustomC, CustomS>
 
-    extend<A extends ModelActions = {}, V extends AnyObject = {}, VS extends AnyObject = {}>(
+    extend<A extends ModelActions = {}, V extends Object = {}, VS extends Object = {}>(
         fn: (self: Instance<this>) => { actions?: A; views?: V; state?: VS }
-    ): IModelType<PROPS, OmitMerge<OTHERS, A & V & VS>, CustomC, CustomS>
+    ): IModelType<PROPS, OTHERS & A & V & VS, CustomC, CustomS>
 
     preProcessSnapshot<NewC = ModelCreationType2<PROPS, CustomC>>(
         fn: (snapshot: NewC) => WithAdditionalProperties<ModelCreationType2<PROPS, CustomC>>
@@ -477,7 +467,7 @@ export class ModelType<
         return this.cloneAndEnhance({ properties })
     }
 
-    volatile<TP extends AnyObject>(fn: (self: Instance<this>) => TP) {
+    volatile<TP extends object>(fn: (self: Instance<this>) => TP) {
         if (typeof fn !== "function") {
             throw new MstError(
                 `You passed an ${typeof fn} to volatile state as an argument, when function is expected`
@@ -514,7 +504,7 @@ export class ModelType<
         })
     }
 
-    extend<A extends ModelActions = {}, V extends AnyObject = {}, VS extends AnyObject = {}>(
+    extend<A extends ModelActions = {}, V extends Object = {}, VS extends Object = {}>(
         fn: (self: Instance<this>) => { actions?: A; views?: V; state?: VS }
     ) {
         const initializer = (self: Instance<this>) => {
@@ -531,15 +521,15 @@ export class ModelType<
         return this.cloneAndEnhance({ initializers: [initializer] })
     }
 
-    views<V extends AnyObject>(fn: (self: Instance<this>) => V) {
+    views<V extends Object>(fn: (self: Instance<this>) => V) {
         const viewInitializer = (self: Instance<this>) => {
             this.instantiateViews(self, fn(self))
             return self
         }
         return this.cloneAndEnhance({ initializers: [viewInitializer] })
     }
 
-    private instantiateViews(self: this["T"], views: AnyObject): void {
+    private instantiateViews(self: this["T"], views: Object): void {
         // check views return
         if (!isPlainObject(views)) {
             throw new MstError(`views initializer should return a plain object containing views`)