feat(types): simplify Model definitions

docs/manual/other-topics/upgrade-to-v7.md

@@ -2,6 +2,15 @@
 
 Sequelize v7 is the next major release after v6. Below is a list of breaking changes to help you upgrade.
 
+## Highlights
+
+Sequelize 7 is a release with lots of breaking changes, but it is also filled with improvements and new features!
+
+### Simplified TypeScript integration
+
+Take a look at our [updated TypeScript guide](https://sequelize.org/v7/manual/typescript.html).
+We hope you'll find that integrating Sequelize with TypeScript in v7 is much easier than in v6.
+
 ## Breaking Changes
 
 ### Support for Node 12 and up
@@ -16,6 +25,92 @@ As a result, the manual typings that were formerly best-effort guesses on top of
 have been removed and all typings are now directly retrieved from the actual TypeScript code.
 You'll likely find many tiny differences which however should be easy to fix.
 
+#### Changes to class-based Model typings
+
+Typings for Models have been greatly simplified. Instead of having to write something like the following:
+
+```typescript
+import { Model, Optional } from 'sequelize';
+
+type UserAttributes = {
+  id: number;
+  firstName: string;
+};
+
+type UserCreationAttributes = Optional<UserAttributes, 'id'>;
+
+class User extends Model<UserAttributes, UserCreationAttributes> {
+  declare id: number;
+  declare firstName: string;
+}
+```
+
+You instead need to write it like this:
+
+```typescript
+import { Model, CreationOptional } from 'sequelize';
+
+class User extends Model<User> {
+  // attribute 'id' has a default value, it can be omitted from Model.create and other creation methods
+  // `CreationOptional` marks it as such in the typings.
+  declare id: CreationOptional<number>;
+  declare firstName: string;
+}
+```
+
+We recommend you take a look at [the updated TypeScript guide for Sequelize](https://sequelize.org/v7/manual/typescript.html).
+
+Note: If you were already using `InferAttributes` & `InferCreationAttributes` in Sequelize 6,
+then your code already looked like the one above. Simply change how you extend the Model class
+from `Model<InferAttributes<User>, InferCreationAttributes<User>>` to `Model<User>`
+
+#### Changes to `sequelize.define`-based model typings
+
+`ModelDefined` has been updated to match how the `Model` class works.
+
+Instead of writing this:
+
+```typescript
+import { ModelDefined, Optional } from 'sequelize';
+
+type UserAttributes = {
+  id: number;
+  firstName: string;
+};
+
+type UserCreationAttributes = Optional<UserAttributes, 'id'>;
+
+const User: ModelDefined<UserAttributes, UserCreationAttributes> = sequelize.define('User', {
+  id: DataTypes.INTEGER,
+  firstName: DataTypes.STRING,
+});
+```
+
+You need to write it like this:
+
+```typescript
+import { ModelDefined, CreationOptional } from 'sequelize';
+
+type UserAttributes = {
+  // attribute 'id' has a default value, it can be omitted from Model.create and other creation methods
+  // `CreationOptional` marks it as such in the typings.
+  id: CreationOptional<number>;
+  firstName: string;
+};
+
+const User: ModelDefined<UserAttributes> = sequelize.define('User', {
+  id: DataTypes.INTEGER,
+  firstName: DataTypes.STRING,
+});
+```
+
+#### Changes to Static Model typings
+
+We improved the typing of `ModelStatic` in Sequelize v6. It now fulfils the role that was previously split
+between `ModelCtor`, `ModelType`, and `ModelStatic`.
+
+It is typically safe to simply replace any use of those with `ModelStatic`.
+
 ### Changes to `ConnectionManager`
 
 *This only impacts you if you used `ConnectionManager` directly.*

package.json

@@ -81,7 +81,7 @@
     "eslint": "8.8.0",
     "eslint-plugin-jsdoc": "37.8.2",
     "eslint-plugin-mocha": "10.0.3",
-    "expect-type": "0.12.0",
+    "expect-type": "0.13.0",
     "fast-glob": "3.2.11",
     "fs-jetpack": "4.3.1",
     "husky": "7.0.4",

src/associations/base.d.ts

@@ -1,9 +1,9 @@
-import { ColumnOptions, Model, ModelCtor, Hookable } from '../model';
+import { ColumnOptions, Model, ModelStatic, Hookable } from '../model';
 
 export abstract class Association<S extends Model = Model, T extends Model = Model> {
   public associationType: string;
-  public source: ModelCtor<S>;
-  public target: ModelCtor<T>;
+  public source: ModelStatic<S>;
+  public target: ModelStatic<T>;
   public isSelfAssociation: boolean;
   public isSingleAssociation: boolean;
   public isMultiAssociation: boolean;

src/associations/belongs-to-many.d.ts

@@ -8,8 +8,7 @@ import {
   InstanceDestroyOptions,
   InstanceUpdateOptions,
   Model,
-  ModelCtor,
-  ModelType,
+  ModelStatic,
   Transactionable,
 } from '../model';
 import { Association, AssociationScope, ForeignKeyOptions, ManyToManyOptions, MultiAssociationAccessors } from './base';
@@ -22,7 +21,7 @@ export interface ThroughOptions {
    * The model used to join both sides of the N:M association.
    * Can be a string if you want the model to be generated by sequelize.
    */
-  model: ModelType | string;
+  model: ModelStatic<any> | string;
 
   /**
    * If true the generated join table will be paranoid
@@ -60,7 +59,7 @@ export interface BelongsToManyOptions extends ManyToManyOptions {
    * The name of the table that is used to join source and target in n:m associations. Can also be a
    * sequelize model if you want to define the junction table yourself and add extra attributes to it.
    */
-  through: ModelType | string | ThroughOptions;
+  through: ModelStatic<any> | string | ThroughOptions;
 
   /**
    * The name of the foreign key in the join table (representing the target model) or an object representing
@@ -98,7 +97,7 @@ export class BelongsToMany<S extends Model = Model, T extends Model = Model> ext
   public sourceKey: string;
   public targetKey: string;
   public accessors: MultiAssociationAccessors;
-  constructor(source: ModelCtor<S>, target: ModelCtor<T>, options: BelongsToManyOptions);
+  constructor(source: ModelStatic<S>, target: ModelStatic<T>, options: BelongsToManyOptions);
 }
 
 /**

src/associations/belongs-to.d.ts

@@ -1,8 +1,7 @@
 import { DataType } from '../data-types';
-import { CreateOptions, CreationAttributes, FindOptions, Model, ModelCtor, SaveOptions } from '../model';
+import { CreateOptions, CreationAttributes, FindOptions, Model, ModelStatic, SaveOptions } from '../model';
 import { Association, AssociationOptions, SingleAssociationAccessors } from './base';
 
-// type ModelCtor<M extends Model> = InstanceType<typeof M>;
 /**
  * Options provided when associating models with belongsTo relationship
  *
@@ -23,7 +22,7 @@ export interface BelongsToOptions extends AssociationOptions {
 
 export class BelongsTo<S extends Model = Model, T extends Model = Model> extends Association<S, T> {
   public accessors: SingleAssociationAccessors;
-  constructor(source: ModelCtor<S>, target: ModelCtor<T>, options: BelongsToOptions);
+  constructor(source: ModelStatic<S>, target: ModelStatic<T>, options: BelongsToOptions);
 }
 
 /**

src/associations/has-many.d.ts

@@ -6,7 +6,7 @@ import {
   FindOptions,
   InstanceUpdateOptions,
   Model,
-  ModelCtor,
+  ModelStatic,
   Transactionable,
 } from '../model';
 import { Association, ManyToManyOptions, MultiAssociationAccessors } from './base';
@@ -30,7 +30,7 @@ export interface HasManyOptions extends ManyToManyOptions {
 
 export class HasMany<S extends Model = Model, T extends Model = Model> extends Association<S, T> {
   public accessors: MultiAssociationAccessors;
-  constructor(source: ModelCtor<S>, target: ModelCtor<T>, options: HasManyOptions);
+  constructor(source: ModelStatic<S>, target: ModelStatic<T>, options: HasManyOptions);
 }
 
 /**

src/associations/has-one.d.ts

@@ -1,5 +1,5 @@
 import { DataType } from '../data-types';
-import { CreateOptions, CreationAttributes, FindOptions, Model, ModelCtor, SaveOptions } from '../model';
+import { CreateOptions, CreationAttributes, FindOptions, Model, ModelStatic, SaveOptions } from '../model';
 import { Association, AssociationOptions, SingleAssociationAccessors } from './base';
 
 /**
@@ -21,7 +21,7 @@ export interface HasOneOptions extends AssociationOptions {
 
 export class HasOne<S extends Model = Model, T extends Model = Model> extends Association<S, T> {
   public accessors: SingleAssociationAccessors;
-  constructor(source: ModelCtor<S>, target: ModelCtor<T>, options: HasOneOptions);
+  constructor(source: ModelStatic<S>, target: ModelStatic<T>, options: HasOneOptions);
 }
 
 /**

src/dialects/abstract/query-interface.d.ts

@@ -9,7 +9,6 @@ import {
   Filterable,
   Poolable,
   ModelStatic,
-  ModelType,
   CreationAttributes,
   Attributes,
 } from '../../model';
@@ -490,7 +489,7 @@ export class QueryInterface {
     insertValues: object,
     updateValues: object,
     where: object,
-    model: ModelType,
+    model: ModelStatic<any>,
     options?: QueryOptions
   ): Promise<object>;
 
@@ -543,13 +542,13 @@ export class QueryInterface {
     tableName: TableName,
     identifier: WhereOptions<any>,
     options?: QueryOptions,
-    model?: ModelType
+    model?: ModelStatic<any>
   ): Promise<object>;
 
   /**
    * Returns selected rows
    */
-  public select(model: ModelType | null, tableName: TableName, options?: QueryOptionsWithWhere): Promise<object[]>;
+  public select(model: ModelStatic<any> | null, tableName: TableName, options?: QueryOptionsWithWhere): Promise<object[]>;
 
   /**
    * Increments a row value
@@ -569,7 +568,7 @@ export class QueryInterface {
     tableName: TableName,
     options: QueryOptionsWithWhere,
     attributeSelector: string | string[],
-    model?: ModelType
+    model?: ModelStatic<any>
   ): Promise<string[]>;
 
   /**

src/dialects/abstract/query.d.ts

@@ -1,6 +1,6 @@
 import { Connection } from './connection-manager';
 import { QueryTypes } from '../../query-types';
-import { Model, ModelType, IncludeOptions } from '../../model';
+import { Model, ModelStatic, IncludeOptions } from '../../model';
 import { Sequelize } from '../../sequelize';
 
 type BindOrReplacements = { [key: string]: unknown } | unknown[];
@@ -13,7 +13,7 @@ export interface AbstractQueryGroupJoinDataOptions {
 
 export interface AbstractQueryOptions {
   instance?: Model;
-  model?: ModelType;
+  model?: ModelStatic<any>;
   type?: QueryTypes;
 
   fieldMap?: boolean;
@@ -79,10 +79,10 @@ export class AbstractQuery {
   /**
    * Model type definition.
    *
-   * @type {ModelType}
+   * @type {ModelStatic}
    * @memberof AbstractQuery
    */
-  public model: ModelType;
+  public model: ModelStatic<any>;
 
   /**
    * Returns the current sequelize instance.