fix: Allows valid non-object JSON to be retrieved in simple-json columns

docs/entities.md

@@ -2,21 +2,29 @@
 
 # Entities
 
-* [What is Entity?](#what-is-entity)
-* [Entity columns](#entity-columns)
-  * [Primary columns](#primary-columns)
-  * [Special columns](#special-columns)
-  * [Spatial columns](#spatial-columns)
-* [Column types](#column-types)
-  * [Column types for `mysql` / `mariadb`](#column-types-for-mysql--mariadb)
-  * [Column types for `postgres` / `cockroachdb`](#column-types-for-postgres)
-  * [Column types for `sqlite` / `cordova` / `react-native` / `expo`](#column-types-for-sqlite--cordova--react-native--expo)
-  * [Column types for `mssql`](#column-types-for-mssql)
-  * [`enum` column type](#enum-column-type)
-  * [`simple-array` column type](#simple-array-column-type)
-  * [`simple-json` column type](#simple-json-column-type)
-  * [Columns with generated values](#columns-with-generated-values)
-* [Column options](#column-options)
+- [Entities](#entities)
+  - [What is Entity?](#what-is-entity)
+  - [Entity columns](#entity-columns)
+    - [Primary columns](#primary-columns)
+    - [Special columns](#special-columns)
+    - [Spatial columns](#spatial-columns)
+  - [Column types](#column-types)
+    - [Column types for `mysql` / `mariadb`](#column-types-for-mysql--mariadb)
+    - [Column types for `postgres`](#column-types-for-postgres)
+    - [Column types for `cockroachdb`](#column-types-for-cockroachdb)
+    - [Column types for `sqlite` / `cordova` / `react-native` / `expo`](#column-types-for-sqlite--cordova--react-native--expo)
+    - [Column types for `mssql`](#column-types-for-mssql)
+    - [Column types for `oracle`](#column-types-for-oracle)
+    - [`enum` column type](#enum-column-type)
+    - [`set` column type](#set-column-type)
+    - [`simple-array` column type](#simple-array-column-type)
+    - [`simple-json` column type](#simple-json-column-type)
+    - [Columns with generated values](#columns-with-generated-values)
+  - [Column options](#column-options)
+  - [Entity inheritance](#entity-inheritance)
+  - [Tree entities](#tree-entities)
+    - [Adjacency list](#adjacency-list)
+    - [Closure table](#closure-table)
 
 ## What is Entity?
 
@@ -196,13 +204,13 @@ There are several special column types with additional functionality available:
 * `@CreateDateColumn` is a special column that is automatically set to the entity's insertion date.
 You don't need to set this column - it will be automatically set.
 
-* `@UpdateDateColumn` is a special column that is automatically set to the entity's update time 
+* `@UpdateDateColumn` is a special column that is automatically set to the entity's update time
 each time you call `save` of entity manager or repository.
 You don't need to set this column - it will be automatically set.
 
 * `@DeleteDateColumn` is a special column that is automatically set to the entity's delete time each time you call soft-delete of entity manager or repository. You don't need to set this column - it will be automatically set. If the @DeleteDateColumn is set, the default scope will be "non-deleted".
 
-* `@VersionColumn` is a special column that is automatically set to the version of the entity (incremental number)  
+* `@VersionColumn` is a special column that is automatically set to the version of the entity (incremental number)
 each time you call `save` of entity manager or repository.
 You don't need to set this column - it will be automatically set.
 
@@ -504,6 +512,12 @@ user.profile = { name: "John", nickname: "Malkovich" };
 Will be stored in a single database column as `{"name":"John","nickname":"Malkovich"}` value.
 When you'll load data from the database, you will have your object/array/primitive back via JSON.parse
 
+When assigning `"null"` (a string) to a `simple-json` type property, it will be treated as a string and stored in its
+string format in the database. That means that it will be stored as the string `"null"` not `NULL` in the database.
+However, using the javascript primitive `null` will persist a `NULL` in the database.
+To avoid storing `"null"` strings in the database, convert your data to a javascript object/array/primitive prior to
+assigning it to your entity.
+
 ### Columns with generated values
 
 You can create column with generated value using `@Generated` decorator. For example:

src/util/DateUtils.ts

@@ -1,4 +1,4 @@
-import {ColumnMetadata} from "../metadata/ColumnMetadata";
+import { ColumnMetadata } from "../metadata/ColumnMetadata";
 
 /**
  * Provides utilities to transform hydrated and persisted data.
@@ -175,12 +175,7 @@ export class DateUtils {
     }
 
     static stringToSimpleJson(value: any) {
-        try {
-            const simpleJSON = JSON.parse(value);
-            return (typeof simpleJSON === "object") ? simpleJSON : {};
-       } catch (err) {
-            return {};
-       }
+        return typeof value === "string" ? JSON.parse(value) : value;
     }
 
     static simpleEnumToString(value: any) {

test/github-issues/4440/entity/Post.ts → test/github-issues/5501/entity/Post.ts

@@ -12,5 +12,4 @@ export class Post {
         nullable: true
     })
     jsonField: any;
-
 }

test/github-issues/5501/issue-5501.ts

@@ -0,0 +1,80 @@
+import "reflect-metadata";
+import { Connection } from "../../../src/connection/Connection";
+import { closeTestingConnections, createTestingConnections, reloadTestingDatabases } from "../../utils/test-utils";
+import { Post } from "./entity/Post";
+import { expect } from "chai";
+
+describe("github issues > #5501 Incorrect data loading from JSON string for column type 'simple-json'", () => {
+
+    let connections: Connection[];
+    before(async () => {
+        connections = await createTestingConnections({
+            entities: [Post],
+            schemaCreate: true,
+            dropSchema: true
+        });
+    });
+    beforeEach(() => reloadTestingDatabases(connections));
+    after(() => closeTestingConnections(connections));
+
+    it("should correctly add/retrieve simple-json field with a string value", () =>
+    Promise.all(connections.map(async (connection) => {
+        const repo = connection.getRepository(Post);
+        const post = new Post();
+        post.id = 1;
+        post.jsonField = "";
+        await repo.save(post);
+        const postFound = await repo.findOne(1);
+        postFound!.id.should.eql(1);
+        postFound!.jsonField.should.eql("");
+    })));
+
+    it("should correctly add/retrieve simple-json field with some object value", () =>
+    Promise.all(connections.map(async (connection) => {
+        const repo = connection.getRepository(Post);
+        const post = new Post();
+        post.id = 1;
+        post.jsonField = {"key": "value"};
+        await repo.save(post);
+        const postFound = await repo.findOne(1);
+        postFound!.id.should.eql(1);
+        postFound!.jsonField.should.eql({"key": "value"});
+    })));
+
+    it("should correctly add/retrieve simple-json field with an array value", () =>
+    Promise.all(connections.map(async (connection) => {
+        const repo = connection.getRepository(Post);
+        const post = new Post();
+        post.id = 1;
+        post.jsonField = [{"key": "value"}];
+        await repo.save(post);
+        const postFound = await repo.findOne(1);
+        postFound!.id.should.eql(1);
+        postFound!.jsonField.should.eql([{"key": "value"}]);
+    })));
+
+    it("should correctly add/retrieve simple-json field with null value", () =>
+    Promise.all(connections.map(async (connection) => {
+        const repo = connection.getRepository(Post);
+        const post = new Post();
+        post.id = 1;
+        post.jsonField = null;
+        await repo.save(post);
+        const postFound = await repo.findOne(1);
+        postFound!.id.should.eql(1);
+        expect(postFound!.jsonField).to.eql(null);
+    })));
+
+    it.only("should correctly add/retrieve simple-json field with 'null' string value", () =>
+    Promise.all(connections.map(async (connection) => {
+        const repo = connection.getRepository(Post);
+        const post = new Post();
+        post.id = 1;
+        post.jsonField = "null";
+        await repo.save(post);
+        const postFound = await repo.findOne(1);
+        postFound!.id.should.eql(1);
+        expect(postFound!.jsonField).to.eql("null");
+    })));
+
+});