fix(save): throw validation error if required key is missing

src/base-model.ts

@@ -22,6 +22,7 @@ import Scan from './scan';
 import { IUpdateActions, buildUpdateActions, put } from './update-operators';
 import ValidationError from './validation-error';
 import { PutCommandInput } from '@aws-sdk/lib-dynamodb/dist-types/commands/PutCommand';
+import { hashKey, item, rangeKey, validItem, validate } from './decorators';
 
 export type KeyValue = string | number | Buffer | boolean | null;
 type SimpleKey = KeyValue;
@@ -34,10 +35,13 @@ const isComposite = (hashKeys_compositeKeys: Keys): hashKeys_compositeKeys is Co
 export default abstract class Model<T> {
   protected tableName: string | undefined;
 
+  @item
   protected item: T | undefined;
 
+  @hashKey
   protected pk: string | undefined;
 
+  @rangeKey
   protected sk: string | undefined;
 
   protected documentClient: DynamoDBDocumentClient;
@@ -188,13 +192,14 @@ export default abstract class Model<T> {
    */
   async save(item: T, options?: Partial<PutCommandInput>): Promise<T>;
 
+  @validate
   async save(
-    item_options?: T | Partial<PutCommandInput>,
+    @validItem item_options?: T | Partial<PutCommandInput>,
     options?: Partial<PutCommandInput>,
   ): Promise<T> {
     // Handle typescript method overloading
     const toSave: T | undefined =
-      item_options != null && this.isItem(item_options) ? item_options : this.item;
+      item_options != null ? item_options as T : this.item;
     const putOptions: Partial<PutCommandInput> | undefined =
       item_options != null && this.isItem(item_options)
         ? options

src/decorators.ts

@@ -0,0 +1,98 @@
+import "reflect-metadata";
+import joi from 'joi';
+import ValidationError from "./validation-error";
+
+const itemParamMetadataKey = Symbol("ItemParam");
+const itemPropertyKey = Symbol("ItemProperty");
+const pkKey = Symbol('PK');
+const skKey = Symbol('SK');
+
+export function hashKey(target: any, key: string) {
+    Reflect.defineProperty(target, key, {
+        get: function () {
+            return this[pkKey];
+        },
+        set: function (newVal: string) {
+            this[pkKey] = newVal
+        }
+    })
+}
+
+export function rangeKey(target: any, key: string) {
+    Reflect.defineProperty(target, key, {
+        get: function () {
+            return this[skKey];
+        },
+        set: function (newVal: string) {
+            this[skKey] = newVal
+        }
+    })
+}
+
+export function item(target: any, key: string) {
+    Reflect.defineProperty(target, key, {
+        get: function () {
+            const pk = this[pkKey]
+            const sk = this[skKey]
+            const item = this[itemPropertyKey];
+            validateSchema(pk, sk, item);
+            return item;
+        },
+        set: function (newVal: unknown) {
+            this[itemPropertyKey] = newVal;
+        }
+    })
+}
+
+export function validItem(
+    target: any,
+    propertyKey: string,
+    parameterIndex: number
+) {
+    const existingParameters: number[] =
+        Reflect.getOwnMetadata(itemParamMetadataKey, target, propertyKey) || [];
+    existingParameters.push(parameterIndex);
+    Reflect.defineMetadata(
+        itemParamMetadataKey,
+        existingParameters,
+        target,
+        propertyKey
+    );
+}
+
+export function validate(
+    target: any,
+    propertyName: string,
+    descriptor: any
+) {
+    const original = descriptor.value;
+    descriptor.value = function (...args: any[]) {
+        const pk = this[pkKey]
+        const sk = this[skKey]
+        const parameters: number[] = Reflect.getOwnMetadata(
+            itemParamMetadataKey,
+            target,
+            propertyName
+        );
+        if (parameters) {
+            for (const parameter of parameters) {
+                validateSchema(pk, sk, args[parameter]);
+            }
+        }
+        return original.apply(this, args);
+    };
+}
+
+function validateSchema(pk: string | undefined, sk: string | undefined, item: unknown) {
+    if (!pk) {
+        throw new Error('Model error: hash key is not defined on this Model');
+    }
+    const schema = joi.object().keys({
+        [pk]: joi.required(),
+        ...(!!sk && { [sk]: joi.required() })
+    }).options({ allowUnknown: true })
+    const { error } = schema.validate(item);
+    if (error) {
+        throw new ValidationError('Validation error', error);
+    }
+}

test/save.spec.ts

@@ -1,7 +1,8 @@
 import { clearTables } from './hooks/create-tables';
-import HashKeyModel from './models/hashkey';
+import HashKeyModel, { HashKeyEntity } from './models/hashkey';
 import TimeTrackedModel from './models/autoCreatedAt-autoUpdatedAt';
 import HashKeyJoiModel from './models/hashkey-joi';
+import CompositeKeyModel, { CompositeKeyEntity } from './models/composite-keys';
 
 describe('The save method', () => {
   beforeEach(async () => {
@@ -64,6 +65,41 @@ describe('The save method', () => {
       expect((e as Error).message.includes('No item to save')).toBe(true);
     }
   });
+  test('should throw an error if the hash keys is missing', async () => {
+    const foo = new HashKeyModel();
+    const item = {
+      string: 'whatever',
+      stringmap: { foo: 'bar' },
+      stringset: ['bar, bar'],
+      number: 43,
+      bool: true,
+      list: ['foo', 42],
+    };
+    try {
+      await foo.save(item as unknown as HashKeyEntity);
+      fail('should throw');
+    } catch (e) {
+      expect((e as Error).message.includes('Validation error')).toBe(true);
+    }
+  });
+  test('should throw an error if the range key is missing', async () => {
+    const foo = new CompositeKeyModel();
+    const item = {
+      hashkey: 'bar',
+      string: 'whatever',
+      stringmap: { foo: 'bar' },
+      stringset: ['bar, bar'],
+      number: 43,
+      bool: true,
+      list: ['foo', 42],
+    };
+    try {
+      await foo.save(item as unknown as CompositeKeyEntity);
+      fail('should throw');
+    } catch (e) {
+      expect((e as Error).message.includes('Validation error')).toBe(true);
+    }
+  });
   test('should throw an error if a Joi schema is specified and validation failed', async () => {
     const foo = new HashKeyJoiModel({
       hashkey: 'bar',