Decorators and some other extras for sequelize (v3 + v4).
- Model Definition
- Usage
- Model association
- Model validation
- Scopes
- Hooks
- Why
() => Model? - Recommendations and limitations
sequelize-typescript requires sequelize
npm install sequelize --save // v4
npm install sequelize@3.30.4 --save // or v3
and reflect-metadata
npm install reflect-metadata --save
npm install sequelize-typescript --save
Your tsconfig.json needs the following flags:
"experimentalDecorators": true,
"emitDecoratorMetadata": trueimport {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.
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> {}| 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) |
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.
Please notice that the timestamps option is false by default. When setting paranoid: true,
remember to also reactivate the timestamps.
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' |
The @Column annotation can be used without passing any parameters. But therefore it is necessary that
the js 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;| Decorator | Description |
|---|---|
@Column |
tries to infer dataType from js type |
@Column(dataType: DateType) |
sets dataType explicitly |
@Column(options: AttributeOptions) |
sets attribute options |
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 |
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 |
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);
}
}Except for minor variations sequelize-typescript will work like pure sequelize. (See sequelize docs)
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']);import {Sequelize} from 'sequelize-typescript';
const sequelize = new Sequelize({
...
modelPaths: [__dirname + '/**/*.model.ts']
});
// or
sequelize.addModels([__dirname + '/**/*.model.ts']);When using a path to resolve the required models, either the class has to be exported as default or if not exported as default, the file should have the same name as the corresponding class:
export default class User extends Model<User> {}
// User.ts
export class User extends Model<User> {}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();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(() => {
});Relations can be described directly in the model by the @HasMany, @HasOne, @BelongsTo, @BelongsToMany
and @ForeignKey annotations.
@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)
@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;
}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)
| 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, through: string, 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.
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[];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( /* ... */);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.
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) { /* ... */}) |
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 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.
(See sequelize docs for more details)
@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 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 += ' 🦄';
}
}@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.
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.
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.
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).
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.