feat: default value attribute (#308)

Co-authored-by: Andrew Scott <[email protected]>

docs/modeling/model-components/attributes.md

@@ -42,7 +42,6 @@ Properties with `[MaxLength]` will generate [client validation](/modeling/model-
 
 Some values of `DataType` when provided to `DataTypeAttribute` on a `string` property will alter the behavior of the [Vue Components](/stacks/vue/coalesce-vue-vuetify/overview.md). See [c-display](/stacks/vue/coalesce-vue-vuetify/components/c-display.md) and See [c-display](/stacks/vue/coalesce-vue-vuetify/components/c-input.md) for details.
 
-
 ### [ForeignKey]
 
 Normally, Coalesce figures out which properties are foreign keys, but if you don't use standard EF naming conventions then you'll need to annotate with `[ForeignKey]` to help out both EF and Coalesce. See the [Entity Framework Relationships](https://docs.microsoft.com/en-us/ef/core/modeling/relationships) documentation for more.
@@ -57,4 +56,8 @@ Primary Keys with `[DatabaseGenerated(DatabaseGeneratedOption.None)]` will be se
 
 ### [NotMapped]
 
-Model properties that aren't mapped to the database should be marked with `[NotMapped]` so that Coalesce doesn't try to load them from the database when [searching](/modeling/model-components/attributes/search.md) or carrying out the [Default Loading Behavior](/modeling/model-components/data-sources.md#default-loading-behavior).
+Model properties that aren't mapped to the database should be marked with `[NotMapped]` so that Coalesce doesn't try to load them from the database when [searching](/modeling/model-components/attributes/search.md) or carrying out the [Default Loading Behavior](/modeling/model-components/data-sources.md#default-loading-behavior).
+
+### [DefaultValue]
+
+Properties with `[DefaultValue]` will receive the specified value when a new ViewModel is instantiated on the client. This enables scenarios like pre-filling a required property with a suggested value.

playground/Coalesce.Domain/Person.cs

@@ -4,6 +4,7 @@
 using Microsoft.EntityFrameworkCore;
 using System;
 using System.Collections.Generic;
+using System.ComponentModel;
 using System.ComponentModel.DataAnnotations;
 using System.ComponentModel.DataAnnotations.Schema;
 using System.Linq;
@@ -77,6 +78,7 @@ public Person()
         /// <summary>
         /// Genetic Gender of the person. 
         /// </summary>
+        [DefaultValue(Genders.NonSpecified)]
         public Genders Gender { get; set; }
 
         [NotMapped]

src/IntelliTect.Coalesce.CodeGeneration.Vue/Generators/Scripts/TsMetadata.cs

@@ -305,6 +305,38 @@ TypeDiscriminator.Enum or
                         TypeDiscriminator.Date
                 ))
                 {
+                    var defaultValue = prop.DefaultValue;
+                    if (defaultValue is not null)
+                    {
+                        if (
+                            prop.Type.TsTypeKind is TypeDiscriminator.String &&
+                            defaultValue is string stringValue
+                        )
+                        {
+                            b.StringProp("defaultValue", stringValue);
+                        }
+                        else if (
+                            prop.Type.TsTypeKind is TypeDiscriminator.Boolean &&
+                            defaultValue is true or false
+                        )
+                        {
+                            b.Prop("defaultValue", defaultValue.ToString().ToLowerInvariant());
+                        }
+                        else if (
+                            prop.Type.TsTypeKind is TypeDiscriminator.Number or TypeDiscriminator.Enum &&
+                            double.TryParse(defaultValue.ToString(), out _)
+                        )
+                        {
+                            b.Prop("defaultValue", defaultValue.ToString());
+                        }
+                        else
+                        {
+                            throw new InvalidOperationException(
+                                $"Default value {defaultValue} does not match property type {prop.Type}, " +
+                                $"or type does not support default values.");
+                        }
+                    }
+
                     List<string> rules = GetValidationRules(prop, (prop.ReferenceNavigationProperty ?? prop).DisplayName);
 
                     if (rules.Count > 0)

src/IntelliTect.Coalesce.Tests/TargetClasses/TestDbContext/ComplexModel.cs

@@ -2,6 +2,7 @@
 using IntelliTect.Coalesce.Models;
 using System;
 using System.Collections.Generic;
+using System.ComponentModel;
 using System.ComponentModel.DataAnnotations;
 using System.ComponentModel.DataAnnotations.Schema;
 using System.Linq;
@@ -99,6 +100,18 @@ public class ComplexModel
 
         public string String { get; set; }
 
+        [DefaultValue("Inigo")]
+        public string StringWithDefault { get; set; }
+
+        [DefaultValue(42)]
+        public int IntWithDefault { get; set; }
+
+        [DefaultValue(Math.PI)]
+        public double DoubleWithDefault { get; set; }
+
+        [DefaultValue(EnumPkId.Value10)]
+        public EnumPkId EnumWithDefault{ get; set; }
+
         [DataType("Color")]
         public string Color { get; set; }
 

src/IntelliTect.Coalesce/TypeDefinition/PropertyViewModel.cs

@@ -244,6 +244,11 @@ propName is null
         /// </summary>
         public bool IsDateOnly => DateType == DateTypeAttribute.DateTypes.DateOnly;
 
+        /// <summary>
+        /// Returns the default value specified by <see cref="DefaultValueAttribute"/>, if present.
+        /// </summary>
+        public object? DefaultValue => this.GetAttributeValue<DefaultValueAttribute>(nameof(DefaultValueAttribute.Value));
+
         /// <summary>
         /// If true, there is an API controller that is serving this type of data.
         /// </summary>

src/coalesce-vue/src/metadata.ts

@@ -302,17 +302,20 @@ export interface StringValue extends ValueMeta<"string"> {
     | "url-image";
 
   readonly rules?: Rules;
+  readonly defaultValue?: string;
 }
 
 /** Represents the usage of a number */
 export interface NumberValue extends ValueMeta<"number"> {
   readonly role: "value" | "foreignKey" | "primaryKey";
   readonly rules?: Rules;
+  readonly defaultValue?: number;
 }
 
 /** Represents the usage of a boolean */
 export interface BooleanValue extends ValueMeta<"boolean"> {
   readonly rules?: Rules;
+  readonly defaultValue?: boolean;
 }
 
 /** Represents the usage of a primitive value (string, number, or bool) */
@@ -353,6 +356,7 @@ export interface UnknownValue extends ValueMeta<"unknown"> {
 export interface EnumValue extends ValueMetaWithTypeDef<"enum", EnumType> {
   readonly role: "value" | "foreignKey" | "primaryKey";
   readonly rules?: Rules;
+  readonly defaultValue?: number;
 }
 
 /** Represents the usage of an 'external type', i.e. an object that is not part of a relational model */

src/coalesce-vue/src/viewmodel.ts

@@ -5,6 +5,7 @@ import {
   markRaw,
   getCurrentInstance,
   toRaw,
+  type Ref,
 } from "vue";
 
 import {
@@ -186,7 +187,7 @@ export abstract class ViewModel<
   }
 
   /** @internal */
-  private _params = ref(new DataSourceParameters());
+  private _params: Ref<DataSourceParameters> = ref(new DataSourceParameters());
 
   /** The parameters that will be passed to `/get`, `/save`, and `/delete` calls. */
   public get $params() {
@@ -451,7 +452,8 @@ export abstract class ViewModel<
   public $saveMode: "surgical" | "whole" = "surgical";
 
   /** @internal */
-  private _savingProps = ref<ReadonlySet<string>>(emptySet);
+  private _savingProps: Ref<ReadonlySet<string>> =
+    ref<ReadonlySet<string>>(emptySet);
 
   /** When `$save.isLoading == true`, contains the properties of the model currently being saved by `$save` (including autosaves).
    *
@@ -1144,7 +1146,7 @@ export abstract class ViewModel<
 
     initialDirtyData?: DeepPartial<TModel> | null
   ) {
-    this.$data = reactive(convertToModel({}, this.$metadata));
+    this.$data = reactive(convertToModel({}, $metadata));
 
     Object.defineProperty(this, "$stableId", {
       enumerable: true, // Enumerable so visible in vue devtools
@@ -1156,6 +1158,23 @@ export abstract class ViewModel<
     if (initialDirtyData) {
       this.$loadDirtyData(initialDirtyData);
     }
+
+    const ctor = this.constructor as any;
+    if (ctor.hasPropDefaults !== false) {
+      for (const prop of Object.values($metadata.props)) {
+        if ("defaultValue" in prop) {
+          ctor.hasPropDefaults ??= true;
+
+          if (!initialDirtyData || !(prop.name in initialDirtyData)) {
+            (this as any)[prop.name] = prop.defaultValue;
+          }
+        }
+      }
+
+      // Cache that this type doesn't have prop defaults so we don't
+      // ever have to loop over the props looking for them on future instances.
+      ctor.hasPropDefaults ??= false;
+    }
   }
 }
 

src/coalesce-vue/test/targets.metadata.ts

@@ -14,10 +14,16 @@ import {
   BehaviorFlags,
 } from "../src/metadata";
 
-const metaBase = (name: string = "model") => {
+export const metaBase = (name: string = "model") => {
+  const pascalName = name.substr(0, 1).toUpperCase() + name.substr(1);
   return {
+    type: "model",
     name: name,
-    displayName: name.substr(0, 1).toUpperCase() + name.substr(1),
+    displayName: pascalName,
+    dataSources: {},
+    methods: {},
+    controllerRoute: pascalName,
+    behaviorFlags: 7 as BehaviorFlags,
   };
 };
 

src/coalesce-vue/test/viewmodel.spec.ts

@@ -16,6 +16,7 @@ import {
   ListViewModel,
   ViewModel,
   ViewModelCollection,
+  defineProps,
 } from "../src/viewmodel";
 
 import {
@@ -32,6 +33,8 @@ import { AxiosResponse } from "axios";
 import { mount } from "@vue/test-utils";
 import { IsVue2 } from "../src/util";
 import { mockEndpoint } from "../src/test-utils";
+import { ModelType } from "../src/metadata";
+import { metaBase } from "./targets.metadata";
 
 function mockItemResult<T>(success: boolean, object: T) {
   return vitest.fn().mockResolvedValue(<AxiosItemResult<T>>{
@@ -2417,6 +2420,76 @@ describe("ViewModel", () => {
       // Should be the exact same reference.
       expect(studentVM.advisor).toBe(advisorVM);
     });
+
+    describe("default values", () => {
+      const meta = {
+        ...metaBase(),
+        get keyProp() {
+          return this.props.id;
+        },
+        get displayProp() {
+          return this.props.name;
+        },
+        props: {
+          id: {
+            name: "id",
+            displayName: "id",
+            role: "primaryKey",
+            type: "number",
+          },
+          name: {
+            name: "name",
+            displayName: "Name",
+            role: "value",
+            type: "string",
+            defaultValue: "Allen",
+          },
+        },
+      } as ModelType;
+
+      class TestVm extends ViewModel<{
+        $metadata: typeof meta;
+        id: number | null;
+        name: string | null;
+      }> {
+        declare id: number | null;
+        declare name: string | null;
+      }
+      defineProps(TestVm as any, meta);
+
+      test("populates default values as dirty", () => {
+        // If default values don't get marked dirty, they won't get saved
+        // which could result in a mismatch between what the user sees in the UI
+        // and what actually happens on the server.
+        const instance = new TestVm(meta, null!);
+
+        expect(instance.name).toBe("Allen");
+        expect(instance.$getPropDirty("name")).toBe(true);
+      });
+
+      test("default values do not overwrite initial data", () => {
+        const instance = new TestVm(meta, null!, { name: "Bob" });
+
+        expect(instance.name).toBe("Bob");
+        expect(instance.$getPropDirty("name")).toBe(true);
+      });
+
+      test("default values fill holes in initial data", () => {
+        const instance = new TestVm(meta, null!, { id: 42 });
+
+        expect(instance.id).toBe(42);
+        expect(instance.name).toBe("Allen");
+      });
+
+      test("default values don't supersede nulls in initial data", () => {
+        // When instantiating a viewmodel from an existing object, deliberate
+        // nulls on the existing object shouldn't be replaced by default values.
+        const instance = new TestVm(meta, null!, { id: 42, name: null });
+
+        expect(instance.id).toBe(42);
+        expect(instance.name).toBe(null);
+      });
+    });
   });
 });