sequelize-typescript

Decorators and some other features for sequelize (v3, v4, v5).

Model Definition
- @Table API
- @Column API
Usage
Model association
Model validation
Scopes
Hooks
Why () => Model?
Recommendations and limitations

Installation

sequelize-typescript requires sequelize

Latest sequelize (v5)

npm install sequelize --save

npm install sequelize-typescript@next --save

Older versions (v4, v3)

npm install sequelize@4 --save
npm install sequelize@3 --save

npm install sequelize-typescript --save

`reflect-metadata`

reflect-metadata is also required

npm install reflect-metadata --save

TypeScript Config

Your tsconfig.json needs the following flags:

"experimentalDecorators": true,
"emitDecoratorMetadata": true

Beta releases

Use next tag for installing beta releases.

npm install sequelize-typescript@next --save

Upcoming major release 🎉

Use canary tag to install an alpha version of the upcoming 1.0.0

npm install sequelize-typescript@canary --save

Model definition

import {Table, Column, Model, HasMany} from 'sequelize-typescript';

@Table
class Person extends Model<Person> {

  @Column
  name: string;

  @Column
  birthday: Date;

  @HasMany(() => Hobby)
  hobbies: Hobby[];
}

The model needs to extend the Model class and has to be annotated with the @Table decorator. All properties that should appear as a column in the database require the @Column annotation.

See more advanced example here.

`@Table`

The @Table annotation can be used without passing any parameters. To specify some more define options, use an object literal (all define options from sequelize are valid):

@Table({
  timestamps: true,
  ...
})
class Person extends Model<Person> {}

Table API

Decorator	Description
`@Table`	sets `options.tableName=<CLASS_NAME>` and `options.modelName=<CLASS_NAME>` automatically
`@Table(options: DefineOptions)`	sets define options (also sets `options.tableName=<CLASS_NAME>` and `options.modelName=<CLASS_NAME>` if not already defined by define options)

Primary key

A primary key (id) will be inherited from base class Model. This primary key is by default an INTEGER and has autoIncrement=true (This behaviour is a native sequelize thing). The id can easily be overridden by marking another attribute as primary key. So either set @Column({primaryKey: true}) or use @PrimaryKey together with @Column.

`timestamps=false`

Please notice that the timestamps option is false by default. When setting paranoid: true, remember to also reactivate the timestamps.

`@CreatedAt`, `@UpdatedAt`, `@DeletedAt`

Annotations to define custom and type safe createdAt, updatedAt and deletedAt attributes:

  @CreatedAt
  creationDate: Date;

  @UpdatedAt
  updatedOn: Date;
  
  @DeletedAt
  deletionDate: Date;

Decorator	Description
`@CreatedAt`	sets `timestamps=true` and `createdAt='creationDate'`
`@UpdatedAt`	sets `timestamps=true` and `updatedAt='updatedOn'`
`@DeletedAt`	sets `timestamps=true`, `paranoid=true` and `deletedAt='deletionDate'`

`@Column`

The @Column annotation can be used without passing any parameters. But therefore it is necessary that the javascript type can be inferred automatically (see Type inference for details).

  @Column
  name: string;

If the type cannot or should not be inferred, use:

import {DataType} from 'sequelize-typescript';

  @Column(DataType.TEXT)
  name: string;

Or for a more detailed column description, use an object literal (all attribute options from sequelize are valid):

  @Column({
    type: DataType.FLOAT,
    comment: 'Some value',
    ...
  })
  value: number;

Column API

Decorator	Description
`@Column`	tries to infer dataType from js type
`@Column(dataType: DateType)`	sets dataType explicitly
`@Column(options: AttributeOptions)`	sets attribute options

Shortcuts

If you're in love with decorators: sequelize-typescript provides some more of them. The following decorators can be used together with the @Column annotation to make some attribute options easier available:

Decorator	Description
`@AllowNull(allowNull?: boolean)`	sets `attribute.allowNull` (default is `true`)
`@AutoIncrement`	sets `attribute.autoIncrement=true`
`@Unique`	sets `attribute.unique=true`
`@Default(value: any)`	sets `attribute.defaultValue` to specified value
`@PrimaryKey`	sets `attribute.primaryKey=true`
`@Comment(value: string)`	sets `attribute.comment` to specified string
Validate annotations	see Model validation

Type inference

The following types can be automatically inferred from javascript type. Others have to be defined explicitly.

Design type	Sequelize data type
`string`	`STRING`
`boolean`	`BOOLEAN`
`number`	`INTEGER`
`Date`	`DATE`
`Buffer`	`BLOB`

Accessors

Get/set accessors do work as well

@Table
class Person extends Model<Person> {

  @Column
  get name(): string {
    return 'My name is ' + this.getDataValue('name');
  }
  
  set name(value: string) {
    this.setDataValue('name', value);
  }
}

Usage

Except for minor variations sequelize-typescript will work like pure sequelize. (See sequelize docs)

Configuration

To make the defined models available, you have to configure a Sequelize instance from sequelize-typescript(!).

import {Sequelize} from 'sequelize-typescript';

const sequelize =  new Sequelize({
        database: 'some_db',
        dialect: 'sqlite',
        username: 'root',
        password: '',
        storage: ':memory:',
        modelPaths: [__dirname + '/models']
});

Before you can use your models you have to tell sequelize where they can be found. So either set modelPaths in the sequelize config or add the required models later on by calling sequelize.addModels([Person]) or sequelize.addModels([__dirname + '/models']):

sequelize.addModels([Person]);
sequelize.addModels(['path/to/models']);

globs

import {Sequelize} from 'sequelize-typescript';

const sequelize =  new Sequelize({
        ...
        modelPaths: [__dirname + '/**/*.model.ts']
});
// or
sequelize.addModels([__dirname + '/**/*.model.ts']);

Model-path resolving

A model is matched to a file by its filename. E.g.

// File User.ts matches the following exported model.
export class User extends Model<User> {}

This is done by comparison of the filename against all exported members. The matching can be customized by specifying the modelMatch function in the configuration object.

For example, if your models are named user.model.ts, and your class is called User, you can match these two by using the following function:

import {Sequelize} from 'sequelize-typescript';

const sequelize =  new Sequelize({
  modelPaths: [__dirname + '/models/**/*.model.ts']
  modelMatch: (filename, member) => {
    return filename.substring(0, filename.indexOf('.model')) === member.toLowerCase();
  },
});

For each file that matches the *.model.ts pattern, the modelMatch function will be called with its exported members. E.g. for the following file

//user.model.ts
import {Table, Column, Model} from 'sequelize-typescript';

export const UserN = 'Not a model';
export const NUser = 'Not a model';

@Table
export class User extends Model<User> {

  @Column
  nickname: string;
}

The modelMatch function will be called three times with the following arguments.

user.model UserN -> false
user.model NUser -> false
user.model User  -> true (User will be added as model)

Another way to match model to file is to make your model the default export.

export default class User extends Model<User> {}

⚠️ When using paths to add models, keep in mind that they will be loaded during runtime. This means that the path may differ from development time to execution time. For instance, using .ts extension within paths will only work together with ts-node.

Build and create

Instantiation and inserts can be achieved in the good old sequelize way

const person = Person.build({name: 'bob', age: 99});
person.save();

Person.create({name: 'bob', age: 99});

but sequelize-typescript also makes it possible to create instances with new:

const person = new Person({name: 'bob', age: 99});
person.save();

Find and update

Finding and updating entries does also work like using native sequelize. So see sequelize docs for more details.

Person
 .findOne()
 .then(person => {
     
     person.age = 100;
     return person.save();
 });

Person
 .update({
   name: 'bobby'
 }, {where: {id: 1}})
 .then(() => {
     
 });

Model association

Relations can be described directly in the model by the @HasMany, @HasOne, @BelongsTo, @BelongsToMany and @ForeignKey annotations.

One-to-many

@Table
class Player extends Model<Player> {

  @Column
  name: string;

  @Column
  num: number;
  
  @ForeignKey(() => Team)
  @Column
  teamId: number;
  
  @BelongsTo(() => Team)
  team: Team;
}

@Table
class Team extends Model<Team> {

  @Column
  name: string;

  @HasMany(() => Player)
  players: Player[];
}

That's all, sequelize-typescript does everything else for you. So when retrieving a team by find

Team
 .findOne({include: [Player]})
 .then(team => {
     
     team.players.forEach(player => console.log(`Player ${player.name}`));
 })

the players will also be resolved (when passing include: Player to the find options)

Many-to-many

@Table
class Book extends Model<Book> { 
  @BelongsToMany(() => Author, () => BookAuthor)
  authors: Author[];
}

@Table
class Author extends Model<Author> {

  @BelongsToMany(() => Book, () => BookAuthor)
  books: Book[];
}

@Table
class BookAuthor extends Model<BookAuthor> {

  @ForeignKey(() => Book)
  @Column
  bookId: number;

  @ForeignKey(() => Author)
  @Column
  authorId: number;
}

Type safe through-table instance access

To access the through-table instance (instanceOf BookAuthor in the upper example) type safely, the type need to be set up manually. For Author model it can be achieved like so:

  @BelongsToMany(() => Book, () => BookAuthor)
  books: Array<Book & {BookAuthor: BookAuthor}>;

One-to-one

For one-to-one use @HasOne(...)(foreign key for the relation exists on the other model) and @BelongsTo(...) (foreign key for the relation exists on this model)

`@ForeignKey`, `@BelongsTo`, `@HasMany`, `@HasOne`, `@BelongsToMany` API

Decorator	Description
`@ForeignKey(relatedModelGetter: () => typeof Model)`	marks property as `foreignKey` for related class
`@BelongsTo(relatedModelGetter: () => typeof Model)`	sets `SourceModel.belongsTo(RelatedModel, ...)` while `as` is key of annotated property and `foreignKey` is resolved from source class
`@BelongsTo(relatedModelGetter: () => typeof Model, foreignKey: string)`	sets `SourceModel.belongsTo(RelatedModel, ...)` while `as` is key of annotated property and `foreignKey` is explicitly specified value
`@BelongsTo(relatedModelGetter: () => typeof Model, options: AssociationOptionsBelongsTo)`	sets `SourceModel.belongsTo(RelatedModel, ...)` while `as` is key of annotated property and `options` are additional association options
`@HasMany(relatedModelGetter: () => typeof Model)`	sets `SourceModel.hasMany(RelatedModel, ...)` while `as` is key of annotated property and `foreignKey` is resolved from target related class
`@HasMany(relatedModelGetter: () => typeof Model, foreignKey: string)`	sets `SourceModel.hasMany(RelatedModel, ...)` while `as` is key of annotated property and `foreignKey` is explicitly specified value
`@HasMany(relatedModelGetter: () => typeof Model, options: AssociationOptionsHasMany)`	sets `SourceModel.hasMany(RelatedModel, ...)` while `as` is key of annotated property and `options` are additional association options
`@HasOne(relatedModelGetter: () => typeof Model)`	sets `SourceModel.hasOne(RelatedModel, ...)` while `as` is key of annotated property and `foreignKey` is resolved from target related class
`@HasOne(relatedModelGetter: () => typeof Model, foreignKey: string)`	sets `SourceModel.hasOne(RelatedModel, ...)` while `as` is key of annotated property and `foreignKey` is explicitly specified value
`@HasOne(relatedModelGetter: () => typeof Model, options: AssociationOptionsHasOne)`	sets `SourceModel.hasOne(RelatedModel, ...)` while `as` is key of annotated property and `options` are additional association options
`@BelongsToMany(relatedModelGetter: () => typeof Model, through: (() => typeof Model))`	sets `SourceModel.belongsToMany(RelatedModel, {through: ThroughModel, ...})` while `as` is key of annotated property and `foreignKey`/`otherKey` is resolved from through class
`@BelongsToMany(relatedModelGetter: () => typeof Model, through: (() => typeof Model), foreignKey: string)`	sets `SourceModel.belongsToMany(RelatedModel, {through: ThroughModel, ...})` while `as` is key of annotated property, `foreignKey` is explicitly specified value and `otherKey` is resolved from through class
`@BelongsToMany(relatedModelGetter: () => typeof Model, through: (() => typeof Model), foreignKey: string, otherKey: string)`	sets `SourceModel.belongsToMany(RelatedModel, {through: ThroughModel, ...})` while `as` is key of annotated property and `foreignKey`/`otherKey` are explicitly specified values
`@BelongsToMany(relatedModelGetter: () => typeof Model, through: string, foreignKey: string, otherKey: string)`	sets `SourceModel.belongsToMany(RelatedModel, {through: throughString, ...})` while `as` is key of annotated property and `foreignKey`/`otherKey` are explicitly specified values
`@BelongsToMany(relatedModelGetter: () => typeof Model, options: AssociationOptionsBelongsToMany)`	sets `SourceModel.belongsToMany(RelatedModel, {through: throughString, ...})` while `as` is key of annotated property and `options` are additional association values, including `foreignKey` and `otherKey`.

Note that when using AssociationOptions, certain properties will be overwritten when the association is built, based on reflection metadata or explicit attribute parameters. For example, as will always be the annotated property's name, and through will be the explicitly stated value.

Multiple relations of same models

sequelize-typescript resolves the foreign keys by identifying the corresponding class references. So if you define a model with multiple relations like

@Table
class Book extends Model<Book> { 

  @ForeignKey(() => Person)
  @Column
  authorId: number;
  
  @BelongsTo(() => Person)
  author: Person; 
  
  @ForeignKey(() => Person)
  @Column
  proofreaderId: number;
  
  @BelongsTo(() => Person)
  proofreader: Person;
}

@Table
class Person extends Model<Person> {

  @HasMany(() => Book)
  writtenBooks: Book[];

  @HasMany(() => Book)
  proofedBooks: Book[];
}

sequelize-typescript cannot know which foreign key to use for which relation. So you have to add the foreign keys explicitly:

  // in class "Books":
  @BelongsTo(() => Person, 'authorId')
  author: Person; 

  @BelongsTo(() => Person, 'proofreaderId')
  proofreader: Person; 
  
  // in class "Person":
  @HasMany(() => Book, 'authorId')
  writtenBooks: Book[];

  @HasMany(() => Book, 'proofreaderId')
  proofedBooks: Book[];

When including a model that has multiple relations you will need to use as property:

  // In the class "books":
  @DefaultScope({
    include: [
      {
        // note as with the @BelongsTo Column name
        as: "author",
        model: () => Person,
      },
    ]
  })
  
  // In a controller or outside of the model
  Book.findAll({ include: [ as: "author", model: Person ] })

Type safe usage of auto generated functions

With the creation of a relation, sequelize generates some method on the corresponding models. So when you create a 1:n relation between ModelA and ModelB, an instance of ModelA will have the functions getModelBs, setModelBs, addModelB, removeModelB, hasModelB. These functions still exist with sequelize-typescript. But TypeScript wont recognize them and will complain if you try to access getModelB, setModelB or addModelB. To make TypeScript happy, the Model.prototype of sequelize-typescript has $set, $get, $add functions.

@Table
class ModelA extends Model<ModelA> {

  @HasMany(() => ModelB)
  bs: ModelB[];
}

@Table
class ModelB extends Model<ModelB> {

  @BelongsTo(() => ModelA)
  a: ModelA;
}

To use them, pass the property key of the respective relation as the first parameter:

const modelA = new ModelA();

modelA.$set('bs', [ /* instance */]).then( /* ... */);
modelA.$add('b', /* instance */).then( /* ... */);
modelA.$get('bs').then( /* ... */);
modelA.$count('bs').then( /* ... */);
modelA.$has('bs').then( /* ... */);
modelA.$remove('bs', /* instance */ ).then( /* ... */);
modelA.$create('bs', /* value */ ).then( /* ... */);

Model validation

Validation options can be set through the @Column annotation, but if you prefer to use separate decorators for validation instead, you can do so by simply adding the validate options as decorators: So that validate.isEmail=true becomes @IsEmail, validate.equals='value' becomes @Equals('value') and so on. Please notice that a validator that expects a boolean is translated to an annotation without a parameter.

See sequelize docs for all validators.

Exceptions

The following validators cannot simply be translated from sequelize validator to an annotation:

Validator	Annotation
`validate.len=[number, number]`	`@Length({max?: number, min?: number})`
`validate[customName: string]`	For custom validators also use the `@Is(...)` annotation: Either `@Is('custom', (value) => { /* ... /})` or with named function `@Is(function custom(value) { / ... */})`

Example

const HEX_REGEX = /^#([A-Fa-f0-9]{6}|[A-Fa-f0-9]{3})$/;

@Table
export class Shoe extends Model<Shoe> {

  @IsUUID(4)
  @PrimaryKey
  @Column
  id: string;

  @Equals('lala')
  @Column
  readonly key: string;

  @Contains('Special')
  @Column
  special: string;

  @Length({min: 3, max: 15})
  @Column
  brand: string;

  @IsUrl
  @Column
  brandUrl: string;

  @Is('HexColor', (value) => {
    if (!HEX_REGEX.test(value)) {
      throw new Error(`"${value}" is not a hex color value.`);
    }
  })
  @Column
  primaryColor: string;

  @Is(function hexColor(value: string): void {
    if (!HEX_REGEX.test(value)) {
      throw new Error(`"${value}" is not a hex color value.`);
    }
  })
  @Column
  secondaryColor: string;

  @Is(HEX_REGEX)
  @Column
  tertiaryColor: string;

  @IsDate
  @IsBefore('2017-02-27')
  @Column
  producedAt: Date;
}

Scopes

Scopes can be defined with annotations as well. The scope options are mostly identical to native sequelize except for the way model classes are referenced. So instead of referencing them directly a getter function () => Model is used instead. (⚠️ For scope functions, models are still referenced directly full() { return {include: [Manufacturer] };}) (See sequelize docs for more details)

`@DefaultScope` and `@Scopes`

@DefaultScope({
  attributes: ['id', 'primaryColor', 'secondaryColor', 'producedAt']
})
@Scopes({
  full: {
    include: [() => Manufacturer]
  },
  yellow: {
    where: {primaryColor: 'yellow'}
  }
})
@Table
export class ShoeWithScopes extends Model<ShoeWithScopes> {

  @Column
  readonly secretKey: string;

  @Column
  primaryColor: string;

  @Column
  secondaryColor: string;

  @Column
  producedAt: Date;

  @ForeignKey(() => Manufacturer)
  @Column
  manufacturerId: number;

  @BelongsTo(() => Manufacturer)
  manufacturer: Manufacturer;
}

Hooks

Hooks can be attached to your models. All Model-level hooks are supported. See the related unit tests for a summary.

Each hook must be a static method. Multiple hooks can be attached to a single method, and you can define multiple methods for a given hook.

The name of the method cannot be the same as the name of the hook (for example, a @BeforeCreate hook method cannot be named beforeCreate). That’s because Sequelize has pre-defined methods with those names.

@Table
export class Person extends Model<Person> {
  @Column
  name: string;

  @BeforeUpdate
  @BeforeCreate
  static makeUpperCase(instance: Person) {
    // this will be called when an instance is created or updated
    instance.name = instance.name.toLocaleUpperCase();
  }

  @BeforeCreate
  static addUnicorn(instance: Person) {
    // this will also be called when an instance is created
    instance.name += ' 🦄';
  }
}

Why `() => Model`?

@ForeignKey(Model) is much easier to read, so why is @ForeignKey(() => Model) so important? When it comes to circular-dependencies (which are in general solved by node for you) Model can be undefined when it gets passed to @ForeignKey. With the usage of a function, which returns the actual model, we prevent this issue.

Recommendations and limitations

One Sequelize instance per model

You cannot add one and the same model to multiple Sequelize instances with differently configured connections. So that one model will only work for one connection.

One model class per file

This is not only good practice regarding design, but also matters for the order of execution. Since Typescript creates a __metadata("design:type", SomeModel) call due to emitDecoratorMetadata compile option, in some cases SomeModel is probably not defined(not undefined!) and would throw a ReferenceError. When putting SomeModel in a separate file, it would look like __metadata("design:type", SomeModel_1.SomeModel), which does not throw an error.

Minification

If you need to minify your code, you need to set tableName and modelName in the DefineOptions for @Table annotation. sequelize-typescript uses the class name as default name for tableName and modelName. When the code is minified the class name will no longer be the originally defined one (So that class User will become class b for example).

Contributing

To contribute you can:

Open issues and participate in discussion of other issues.
Fork the project to open up PR's.
Update the types of Sequelize.
Anything else constructively helpful.

In order to open a pull request please:

Create a new branch.
Run tests locally (npm install && npm run build && npm run cover) and ensure your commits don't break the tests.
Document your work well with commit messages, a good PR description, comments in code when necessary, etc.

In order to update the types for sequelize please go to the Definitely Typed repo, it would also be a good idea to open a PR into sequelize so that Sequelize can maintain its own types, but that might be harder than getting updated types into microsoft's repo. The Typescript team is slowly trying to encourage npm package maintainers to maintain their own typings, but Microsoft still has dedicated and good people maintaining the DT repo, accepting PR's and keeping quality high.

Keep in mind sequelize-typescript does not provide typings for sequelize - these are seperate things. A lot of the types in sequelize-typescript augment, refer to, or extend what sequelize already has.

Files

README.md

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