Cannot import decorators-legacy in V7

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I have read the contribution guidelines

Bug Description

The documentation explicitly indicates to use decorators to define all aspects related to a model.
From types, to relationships, and more.

However, I personally cannot get it to work, due to this issue in my VSCode editor

Cannot find module '@sequelize/core/decorators-legacy' or its corresponding type declarations.ts(2307)

Reproducible Example

I use TypeScript
Everything works fine without importing or trying to use decorators. I.e.:

import { Model, DataTypes, InferAttributes, InferCreationAttributes, CreationOptional } from '@sequelize/core'
import { RequestType } from '../types'
import { sequelize } from '../db'

class Request extends Model<InferAttributes<Request>, InferCreationAttributes<Request>> {
  declare id: CreationOptional<number>
  declare requestType: string
  declare requestData: object
  declare requester: string
  declare createdAt: CreationOptional<Date>
  declare updatedAt: CreationOptional<Date>
}

Request.init({
  id: {
    type: DataTypes.INTEGER,
    primaryKey: true,
    autoIncrement: true
  },
  requestType: {
    type: DataTypes.ENUM(
      RequestType.EXPENV_AZURE,
      RequestType.EXPENV_GCP,
      RequestType.VM_AZURE,
      RequestType.VM_GCP,
      RequestType.RPA_AZURE,
      RequestType.RPA_GCP,
      RequestType.AZURE_RG
    ),
    allowNull: true
  },
  requestData: {
    type: DataTypes.JSON,
    allowNull: false
  },
  requester: {
    type: DataTypes.STRING,
    allowNull: false
  },
  createdAt: {
    type: DataTypes.DATE
  },
  updatedAt: {
    type: DataTypes.DATE
  }
}, { sequelize })

The sequelize directory inside node_modules seems to have all the requested data

However, and as per a standard example on this page, the usual flow to use decorators

import { Model, DataTypes, InferAttributes, InferCreationAttributes, CreationOptional, NonAttribute } from '@sequelize/core'
import { PrimaryKey, Attribute, AutoIncrement, NotNull, HasMany, BelongsTo } from '@sequelize/core/decorators-legacy'

has the second line, no matter what else I have in my file, always throw this error:
Cannot find module '@sequelize/core/decorators-legacy' or its corresponding type declarations.ts(2307)

What do you expect to happen?

Find the module and not throw that error

What is actually happening?

Environment

Sequelize version:

$ npm list @sequelize/core
db-operator@1.0.0 
└── @sequelize/core@7.0.0-alpha.27

Node.js version:

$ node -v
v18.12.1

If TypeScript related: TypeScript version:

npm list typescript
db-operator@1.0.0
├─┬ ts-jest@29.1.1
│ └── typescript@5.1.6
└─┬ ts-standard@12.0.2
  ├─┬ @typescript-eslint/eslint-plugin@5.62.0
  │ └─┬ tsutils@3.21.0
  │   └── typescript@5.1.6 deduped
  ├─┬ eslint-config-standard-with-typescript@23.0.0
  │ └── typescript@5.1.6 deduped
  └── typescript@5.1.6 deduped

tsconfig.json

{
  "compilerOptions": {
    "allowJs": false,
    "declaration": true,
    "experimentalDecorators": true,
    "emitDecoratorMetadata": true,
    "module": "commonjs",
    "moduleResolution": "node",
    "outDir": "dist",
    "rootDir": ".",
    "skipLibCheck": true,
    "sourceMap": true,
    "strict": true,
    "strictNullChecks": true,
    "target": "es6",
    "types": ["node"],
  },
}

Database & Version: MySQL 8
Connector library & Version: mysql2@3.5.2

Would you be willing to resolve this issue by submitting a Pull Request?

Yes, I have the time and I know how to start.
Yes, I have the time but I will need guidance.
No, I don't have the time, but my company or I are supporting Sequelize through donations on OpenCollective.
No, I don't have the time, and I understand that I will need to wait until someone from the community or maintainers is interested in resolving my issue.

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You need to set your tsconfig moduleResolution option to node16 or nodenext: https://www.typescriptlang.org/docs/handbook/esm-node.html#packagejson-exports-imports-and-self-referencing

Thank you ephys for the reply. I will try it, but it doesn't make sense.
Your own tsconfig has moduleResolution set just to node, like I do

If this turns out to be the issue, may I suggest that this is clearly reflected somewhere in the documentation?

Our own tsconfig should not be used as an example, it's overly complicated because we try to support multiple versions of TypeScript

I've converted this to a documentation issue

Our own tsconfig should not be used as an example, it's overly complicated because we try to support multiple versions of TypeScript

I've converted this to a documentation issue

It would be handy to have an example tsconfig.json that's suitable to use in a fresh V7 project

This is pretty awful, I can't lie. NodeNext is practically unusable due to

lack of (good) documentation/examples
Impenetrable path aliasing (I vehemently reject ../../, that is an abomination)

The exports block is a lovely QoL feature when you're on NodeNext, but NodeNext being required to use v7 at all? 😩

You can have path aliasing in your own project by configuring exports in your own package.json

The explanation for the different type of moduleResolutions is described here: https://www.typescriptlang.org/tsconfig#moduleResolution
If that is not sufficient, I would recommend opening an issue on the TypeScript repo about it instead

You don't technically have to use Node16/NodeNext/Bundler (though I don't see why you wouldn't use the ts module resolution that accurately replicates how node resolves modules if you're using node). You can configure paths, or use resolvePackageJsonExports instead

yeah, sorry. Was very frustrated last night. Turned out my path aliasing was working just fine but needed the .js extensions - the error was incredibly vague ('cannot resolve...')

We have opened #583 to document this. Are we missing anything?

As mentioned in sequelize/sequelize#16866, we also need to update the SSCCE repo's tsconfig

FWIW, you can set moduleResolution to "Bundler" and it also works. (TS notes that "This is the recommended setting in TypeScript 5.0+ for applications that use a bundler.")

I have Sequelize v7 with decorators working in a Next.js 14 project, and I'm basically using the default create-t3-app tsconfig.json. Posting this here in case anyone needs a similar resolution:

{
  "compilerOptions": {
    /* Base Options */
    "esModuleInterop": true,
    "skipLibCheck": true,
    "target": "ES2022",
    "allowJs": true,
    "resolveJsonModule": true,
    "moduleDetection": "force",
    "isolatedModules": true,
    /* Sequelize */
    "experimentalDecorators": true,
    "emitDecoratorMetadata": true,
    "allowImportingTsExtensions": true,
    /* Strictness */
    "strict": true,
    "noUncheckedIndexedAccess": true,
    "forceConsistentCasingInFileNames": true,
    "checkJs": true,
    /* Bundled projects */
    "lib": ["dom", "dom.iterable", "ES2022"],
    "noEmit": true,
    "module": "ESNext",
    "moduleResolution": "Bundler",
    "jsx": "preserve",
    "plugins": [{ "name": "next" }],
    "incremental": true,
    /* Path aliases */
    "baseUrl": ".",
    "paths": {
      "@/*": ["./*"]
    },
    /* Needed for ts-node */
    "typeRoots": ["**/*.d.ts"]
  },
  "include": [
    ".eslintrc.cjs",
    "next-env.d.ts",
    "**/*.ts",
    "**/*.tsx",
    "**/*.cjs",
    "**/*.js",
    ".next/types/**/*.ts"
  ],
  "exclude": ["node_modules"],
  "ts-node": {
    "esm": true
  }
}

By the given tsconfig.json, getting below error

TypeError [ERR_UNKNOWN_FILE_EXTENSION]: Unknown file extension ".ts"

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Cannot import decorators-legacy in V7 #552

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Bug Description

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What is actually happening?

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Cannot import decorators-legacy in V7 #552

Description

Issue Creation Checklist

Bug Description

Reproducible Example

What do you expect to happen?

What is actually happening?

Environment

Would you be willing to resolve this issue by submitting a Pull Request?

Activity

ephys commented on Jul 25, 2023

w0rldart commented on Jul 26, 2023

ephys commented on Aug 15, 2023

w0rldart commented on Aug 15, 2023

Lordfirespeed commented on Sep 15, 2023

ephys commented on Sep 15, 2023

Lordfirespeed commented on Sep 15, 2023

WikiRik commented on Sep 15, 2023

ephys commented on Dec 13, 2023

johneatmon commented on Dec 13, 2023

yharishy commented on Apr 4, 2025

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