more sequelize stuff

rootfs_overlay/lkmc/nodejs/assert_cheat.js

@@ -0,0 +1,5 @@
+#!/usr/bin/env node
+
+const assert = require('assert');
+
+assert(1 + 1 === 2)

rootfs_overlay/lkmc/nodejs/list_object_methods.js

@@ -0,0 +1,47 @@
+#!/usr/bin/env node
+
+// https://stackoverflow.com/questions/2257993/how-to-display-all-methods-of-an-object/67975040#67975040
+// https://stackoverflow.com/questions/30881632/es6-iterate-over-class-methods/47714550#47714550
+
+const isGetter = (x, name) => (Object.getOwnPropertyDescriptor(x, name) || {}).get
+const isFunction = (x, name) => typeof x[name] === "function";
+const deepFunctions = x =>
+  x && x !== Object.prototype &&
+  Object.getOwnPropertyNames(x)
+    .filter(name => isGetter(x, name) || isFunction(x, name))
+    .concat(deepFunctions(Object.getPrototypeOf(x)) || []);
+const distinctDeepFunctions = x => Array.from(new Set(deepFunctions(x)));
+const getMethods = (obj) => distinctDeepFunctions(obj).filter(
+    name => name !== "constructor" && !~name.indexOf("__"));
+
+// Example usage.
+
+class BaseClass {
+  constructor() {
+    this.baseProp = 1
+  }
+  override() { return 1; }
+  baseMethod() { return 2; }
+}
+
+class DerivedClass extends BaseClass {
+  constructor() {
+    super()
+    this.derivedProp = 2
+  }
+  override() { return 3; }
+  get myGetter() { return 4; }
+  static myStatic() { return 5; }
+}
+
+const obj = new DerivedClass();
+const methods = getMethods(obj)
+methods.sort()
+const assert = require('assert')
+const util = require('util')
+assert(methods[0] === 'baseMethod')
+assert(methods[1] === 'myGetter')
+assert(methods[2] === 'override')
+assert(methods.length === 3)
+
+console.log(getMethods(Math))

rootfs_overlay/lkmc/nodejs/object_to_string.js

@@ -29,15 +29,19 @@ let my_object = new MyClassUtilInspectCustom(1, 2, new MyClassUtilInspectCustomS
 // Affected.
 console.log('util.inspect');
 console.log(util.inspect(my_object));
+console.log();
 // Affected.
 console.log('console.log');
 console.log(my_object);
+console.log();
 // Not affected.
 console.log('toString');
 console.log(my_object.toString());
+console.log();
 // Not affected.
 console.log('toString implicit +');
 console.log('implicit ' + my_object);
+console.log();
 // Not affected.
 console.log('template string');
 console.log(`${my_object}`);
@@ -68,15 +72,20 @@ my_object = new MyClassToString(1, 2, new MyClassToStringSubobject(3, 4));
 // Affected.
 console.log('util.inspect');
 console.log(util.inspect(my_object));
+console.log();
 // Affected.
 console.log('console.log');
 console.log(my_object);
+console.log();
 // Affected.
 console.log('toString');
 console.log(my_object.toString());
+console.log();
 // Affected.
 console.log('toString implicit +');
 console.log('implicit ' + my_object);
+console.log();
 // Affected.
 console.log('template string');
 console.log(`${my_object}`);
+console.log();

rootfs_overlay/lkmc/nodejs/package.json

@@ -9,8 +9,8 @@
     "pg": "8.5.1",
     "pg-hstore": "2.3.3",
     "sequelize": "6.5.1",
-    "sqlite3": "^5.0.2",
-    "ts-node": "^10.0.0"
+    "sqlite3": "5.0.2",
+    "ts-node": "10.0.0"
   },
   "devDependencies": {},
   "scripts": {

rootfs_overlay/lkmc/nodejs/sequelize/association.js

@@ -65,6 +65,7 @@ await Comment.create({body: 'u1c0', UserId: u1.id});
   console.log(Object.getOwnPropertyNames(u0));
   const u0Comments = await u0.getComments({
     include: [{ model: User }],
+    order: [['id', 'ASC']],
   });
   assert(u0Comments[0].body === 'u0c0');
   assert(u0Comments[1].body === 'u0c1');
@@ -143,6 +144,5 @@ await Comment.create({body: 'u1c0', UserId: u1.id});
     //assert(u0Comments[1].author.name === 'u0');
   }
 }
-
 await sequelize.close();
 })();

rootfs_overlay/lkmc/nodejs/sequelize/association_many_to_many.js

@@ -0,0 +1,132 @@
+#!/usr/bin/env node
+
+// https://stackoverflow.com/questions/22958683/how-to-implement-many-to-many-association-in-sequelize/67973948#67973948
+
+const assert = require('assert');
+const path = require('path');
+
+const { Sequelize, DataTypes } = require('sequelize');
+
+const sequelize = new Sequelize({
+  dialect: 'sqlite',
+  storage: 'tmp.' + path.basename(__filename) + '.sqlite',
+});
+
+(async () => {
+
+// Create the tables.
+const User = sequelize.define('User', {
+  name: { type: DataTypes.STRING },
+}, {});
+const Post = sequelize.define('Post', {
+  body: { type: DataTypes.STRING },
+}, {});
+// UserLikesPost is the name of the relation table.
+// Sequelize creates it automatically for us.
+// On SQLite that table looks like this:
+// CREATE TABLE `UserLikesPost` (
+//   `createdAt` DATETIME NOT NULL,
+//   `updatedAt` DATETIME NOT NULL,
+//   `UserId` INTEGER NOT NULL REFERENCES `Users` (`id`) ON DELETE CASCADE ON UPDATE CASCADE,
+//   `PostId` INTEGER NOT NULL REFERENCES `Posts` (`id`) ON DELETE CASCADE ON UPDATE CASCADE,
+//   PRIMARY KEY (`UserId`, `PostId`)
+// );
+User.belongsToMany(Post, {through: 'UserLikesPost'});
+Post.belongsToMany(User, {through: 'UserLikesPost'});
+await sequelize.sync({force: true});
+
+// Create some users and likes.
+
+const user0 = await User.create({name: 'user0'})
+const user1 = await User.create({name: 'user1'})
+const user2 = await User.create({name: 'user2'})
+
+const post0 = await Post.create({body: 'post0'});
+const post1 = await Post.create({body: 'post1'});
+const post2 = await Post.create({body: 'post2'});
+
+// Autogenerated add* methods
+
+// Make user0 like post0
+await user0.addPost(post0)
+// Make user0 and user2 like post1
+await post1.addUsers([user0, user2])
+
+// Autogenerated get* methods
+
+// Get likes by a user.
+
+const user0Likes = await user0.getPosts({order: [['body', 'ASC']]})
+assert(user0Likes[0].body === 'post0');
+assert(user0Likes[1].body === 'post1');
+assert(user0Likes.length === 2);
+
+const user1Likes = await user1.getPosts({order: [['body', 'ASC']]})
+assert(user1Likes.length === 0);
+
+const user2Likes = await user2.getPosts({order: [['body', 'ASC']]})
+assert(user2Likes[0].body === 'post1');
+assert(user2Likes.length === 1);
+
+// Get users that liked a given likes.
+
+const post0Likers = await post0.getUsers({order: [['name', 'ASC']]})
+assert(post0Likers[0].name === 'user0');
+assert(post0Likers.length === 1);
+
+const post1Likers = await post1.getUsers({order: [['name', 'ASC']]})
+assert(post1Likers[0].name === 'user0');
+assert(post1Likers[1].name === 'user2');
+assert(post1Likers.length === 2);
+
+const post2Likers = await post2.getUsers({order: [['name', 'ASC']]})
+assert(post1Likers[0].name === 'user0');
+assert(post1Likers[1].name === 'user2');
+assert(post1Likers.length === 2);
+
+// Autogenerated has* methods
+
+// Check if user likes post.
+assert( await user0.hasPost(post0))
+assert( await user0.hasPost(post1))
+assert(!await user0.hasPost(post2))
+
+// Check if post is liked by user.
+assert( await post0.hasUser(user0))
+assert(!await post0.hasUser(user1))
+assert(!await post0.hasUser(user2))
+
+// AND of multiple has checks at once.
+assert( await user0.hasPosts([post0, post1]))
+assert(!await user0.hasPosts([post0, post1, post2]))
+
+// Autogenerated count* methods
+assert(await user0.countPosts() === 2)
+assert(await post0.countUsers() === 1)
+
+// Autogenerated remove* method
+
+// user0 doesn't like post0 anymore.
+await user0.removePost(post0)
+// user0 and user 2 don't like post1 anymore.
+await post1.removeUsers([user0, user2])
+// Check that no-one likes anything anymore.
+assert(await user0.countPosts() === 0)
+assert(await post0.countUsers() === 0)
+
+// Autogenerated create* method
+// Create a new post and automatically make user0 like it.
+const post3 = await user0.createPost({'body': 'post3'})
+assert(await user0.hasPost(post3))
+assert(await post3.hasUser(user0))
+
+// Autogenerated set* method
+// Make user0 like exactly these posts. Unlike anything else.
+await user0.setPosts([post1, post2])
+assert(!await user0.hasPost(post0))
+assert( await user0.hasPost(post1))
+assert( await user0.hasPost(post2))
+assert(!await user0.hasPost(post3))
+
+await sequelize.close();
+})();

rootfs_overlay/lkmc/nodejs/sequelize/association_many_to_many_custom_table.js

@@ -0,0 +1,90 @@
+#!/usr/bin/env node
+
+// https://stackoverflow.com/questions/22958683/how-to-implement-many-to-many-association-in-sequelize/67973948#67973948
+
+const assert = require('assert');
+const path = require('path');
+
+const { Sequelize, DataTypes } = require('sequelize');
+
+const sequelize = new Sequelize({
+  dialect: 'sqlite',
+  storage: 'tmp.' + path.basename(__filename) + '.sqlite',
+});
+
+(async () => {
+
+// Create the tables.
+const User = sequelize.define('User', {
+  name: { type: DataTypes.STRING },
+}, {});
+const Post = sequelize.define('Post', {
+  body: { type: DataTypes.STRING },
+}, {});
+const UserLikesPost = sequelize.define('UserLikesPost', {
+  UserId: {
+    type: DataTypes.INTEGER,
+    references: {
+      model: User,
+      key: 'id'
+    }
+  },
+  PostId: {
+    type: DataTypes.INTEGER,
+    references: {
+      model: Post,
+      key: 'id'
+    }
+  },
+  score: {
+    type: DataTypes.INTEGER,
+  },
+});
+// UserLikesPost is the name of the relation table.
+// Sequelize creates it automatically for us.
+// On SQLite that table looks like this:
+// CREATE TABLE `UserLikesPost` (
+//   `createdAt` DATETIME NOT NULL,
+//   `updatedAt` DATETIME NOT NULL,
+//   `UserId` INTEGER NOT NULL REFERENCES `Users` (`id`) ON DELETE CASCADE ON UPDATE CASCADE,
+//   `PostId` INTEGER NOT NULL REFERENCES `Posts` (`id`) ON DELETE CASCADE ON UPDATE CASCADE,
+//   `Score` INTEGER,
+//   PRIMARY KEY (`UserId`, `PostId`)
+// );
+User.belongsToMany(Post, {through: UserLikesPost});
+Post.belongsToMany(User, {through: UserLikesPost});
+await sequelize.sync({force: true});
+
+// Create some users and likes.
+
+const user0 = await User.create({name: 'user0'})
+const user1 = await User.create({name: 'user1'})
+const user2 = await User.create({name: 'user2'})
+
+const post0 = await Post.create({body: 'post0'});
+const post1 = await Post.create({body: 'post1'});
+const post2 = await Post.create({body: 'post2'});
+
+// Autogenerated add* methods
+
+// Make user0 like post0
+await user0.addPost(post0, {through: { score: 1 }})
+
+const user0Likes = await user0.getPosts({order: [['body', 'ASC']]})
+assert(user0Likes[0].body === 'post0');
+assert(user0Likes[0].UserLikesPost.score === 1);
+assert(user0Likes.length === 1);
+
+// TODO: this doesn't work. Possible at all in a single addUsers call?
+// Make user0 and user2 like post1
+// This method automatically generated.
+//await post1.addUsers(
+//  [user0, user2],
+//  {through: [
+//    {score: 2},
+//    {score: 3},
+//  ]}
+//)
+
+await sequelize.close();
+})();

rootfs_overlay/lkmc/nodejs/sequelize/association_many_to_many_same_model.js

@@ -0,0 +1,40 @@
+#!/usr/bin/env node
+
+// https://stackoverflow.com/questions/22958683/how-to-implement-many-to-many-association-in-sequelize/67973948#67973948
+
+const assert = require('assert');
+const path = require('path');
+
+const { Sequelize, DataTypes } = require('sequelize');
+
+const sequelize = new Sequelize({
+  dialect: 'sqlite',
+  storage: 'tmp.' + path.basename(__filename) + '.sqlite',
+});
+
+(async () => {
+
+// Create the tables.
+const User = sequelize.define('User', {
+  name: { type: DataTypes.STRING },
+}, {});
+User.belongsToMany(User, {through: 'UserFollowsUser', as: 'Follow'});
+await sequelize.sync({force: true});
+
+// Create some users.
+
+const user0 = await User.create({name: 'user0'})
+const user1 = await User.create({name: 'user1'})
+const user2 = await User.create({name: 'user2'})
+const user3 = await User.create({name: 'user3'})
+
+// Make user0 follow user1 and user2
+await user0.addFollow(user1)
+await user0.addFollow(user2)
+const user0Follows = await user0.getFollow({order: [['name', 'ASC']]})
+assert(user0Follows[0].name === 'user1');
+assert(user0Follows[1].name === 'user2');
+assert(user0Follows.length === 2);
+
+await sequelize.close();
+})();