From 7421e595875354145c3270d90baf28a9c70002da Mon Sep 17 00:00:00 2001
From: Ivica Batinic <ivica.batinic@infinum.hr>
Date: Sat, 22 May 2021 11:40:52 +0200
Subject: [PATCH] Add support for compare fn on View.sortMethod

---
 packages/datx/src/View.ts         | 12 ++++++--
 packages/datx/src/helpers/view.ts |  5 ++++
 packages/datx/src/types.ts        |  3 ++
 packages/datx/test/view.test.ts   | 46 ++++++++++++++++++++++++++++---
 4 files changed, 59 insertions(+), 7 deletions(-)
 create mode 100644 packages/datx/src/helpers/view.ts
 create mode 100644 packages/datx/src/types.ts

diff --git a/packages/datx/src/View.ts b/packages/datx/src/View.ts
index 7f446284d..b31082bbd 100644
--- a/packages/datx/src/View.ts
+++ b/packages/datx/src/View.ts
@@ -3,6 +3,7 @@ import { IArraySplice, IRawModel, mapItems, mobx, removeFromArray, replaceInArra
 import { ToMany } from './buckets/ToMany';
 import { error } from './helpers/format';
 import { getModelId, getModelType, isReference } from './helpers/model/utils';
+import { isPropertySelectorFn } from './helpers/view';
 import { IIdentifier } from './interfaces/IIdentifier';
 import { IModelConstructor } from './interfaces/IModelConstructor';
 import { IModelRef } from './interfaces/IModelRef';
@@ -11,17 +12,18 @@ import { IType } from './interfaces/IType';
 import { TChange } from './interfaces/TChange';
 import { PureCollection } from './PureCollection';
 import { PureModel } from './PureModel';
+import { SortMethod } from './types';
 
 export class View<T extends PureModel = PureModel> extends ToMany<T> {
   public readonly modelType: IType;
 
   @mobx.observable
-  public sortMethod?: string | ((item: T) => any);
+  public sortMethod?: SortMethod<T>;
 
   constructor(
     modelType: IModelConstructor<T> | IType,
     protected __collection: PureCollection,
-    sortMethod?: string | ((item: T) => any),
+    sortMethod?: SortMethod<T>,
     models: Array<IIdentifier | T> = [],
     public unique: boolean = false,
   ) {
@@ -50,7 +52,11 @@ export class View<T extends PureModel = PureModel> extends ToMany<T> {
           ? (item): any => item[this.sortMethod as 'string']
           : this.sortMethod;
 
-      list.sort((a: T, b: T) => (sortFn(a) === sortFn(b) ? 0 : sortFn(a) > sortFn(b) ? 1 : -1));
+      if (isPropertySelectorFn(sortFn)) {
+        list.sort((a: T, b: T) => (sortFn(a) === sortFn(b) ? 0 : sortFn(a) > sortFn(b) ? 1 : -1));
+      } else {
+        list.sort(sortFn);
+      }
     }
 
     const instances = mobx.observable.array(list, { deep: false });
diff --git a/packages/datx/src/helpers/view.ts b/packages/datx/src/helpers/view.ts
new file mode 100644
index 000000000..44b830e47
--- /dev/null
+++ b/packages/datx/src/helpers/view.ts
@@ -0,0 +1,5 @@
+import { PropertySelectorFn, CompareFn } from '../types';
+
+export function isPropertySelectorFn<T>(fn: PropertySelectorFn<T> | CompareFn<T>): fn is PropertySelectorFn<T> {
+  return fn.length === 1;
+}
diff --git a/packages/datx/src/types.ts b/packages/datx/src/types.ts
new file mode 100644
index 000000000..554f2f7e3
--- /dev/null
+++ b/packages/datx/src/types.ts
@@ -0,0 +1,3 @@
+export type PropertySelectorFn<T> = (item: T) => any;
+export type CompareFn<T> = (a: T, b: T) => number;
+export type SortMethod<T> = string | PropertySelectorFn<T> | CompareFn<T>;
diff --git a/packages/datx/test/view.test.ts b/packages/datx/test/view.test.ts
index 4c0fb7f0a..86c9dc983 100644
--- a/packages/datx/test/view.test.ts
+++ b/packages/datx/test/view.test.ts
@@ -239,6 +239,44 @@ describe('View', () => {
     expect(item2b && item2b.key).toBe(2);
   });
 
+  it('should be able to sort with compare function and non-unique props', () => {
+    class Foo extends Model {
+      public static type = 'foo';
+
+      @Attribute()
+      public notUnique!: number;
+      @Attribute()
+      public unique!: number;
+    }
+    class AppCollection extends Collection {
+      public static types = [Foo];
+    }
+
+    const collection = new AppCollection();
+    const foos = collection.add([{ notUnique: 2, unique: 3 }, { notUnique: 2, unique: 1 }, { notUnique: 1, unique: 2 }], Foo);
+
+    const compareFn = (a: Foo, b: Foo): number => {
+      if (a.notUnique === b.notUnique){
+        return a.unique < b.unique ? -1 : 1
+      } else {
+        return a.notUnique < b.notUnique ? -1 : 1
+      }
+    }
+
+    const viewInstance = new View(Foo, collection, compareFn, foos);
+
+    expect(viewInstance.length).toBe(3);
+    const item0a = viewInstance.list[0];
+    const item1a = viewInstance.list[1];
+    const item2a = viewInstance.list[2];
+    expect(item0a && item0a.notUnique).toBe(1);
+    expect(item0a && item0a.unique).toBe(2);
+    expect(item1a && item1a.notUnique).toBe(2);
+    expect(item1a && item1a.unique).toBe(1);
+    expect(item2a && item2a.notUnique).toBe(2);
+    expect(item2a && item2a.unique).toBe(3);
+  });
+
   it('should be able to remove models', () => {
     class Foo extends Model {
       public static type = 'foo';
@@ -277,19 +315,19 @@ describe('View', () => {
     if (mobx.useRealMobX) {
       viewInstance.list.push(foo1);
       expect(viewInstance).toHaveLength(4);
-  
+
       viewInstance.list.unshift(foo2);
       expect(viewInstance).toHaveLength(5);
-  
+
       viewInstance.list.splice(2, 2);
       expect(viewInstance).toHaveLength(3);
     } else {
       viewInstance.list = [...viewInstance.list, foo1];
       expect(viewInstance).toHaveLength(4);
-  
+
       viewInstance.list = [foo2, ...viewInstance.list];
       expect(viewInstance).toHaveLength(5);
-  
+
       viewInstance.list = [...viewInstance.list.slice(0, 2), ...viewInstance.list.slice(4)];
       expect(viewInstance).toHaveLength(3);
     }