Compiler declares variable with let causing ReferenceError when trying to access it before initialization

[sergii-nosachenko]

Describe the bug

When trying to execute the compiled project it fails with ReferenceError: Cannot access 'X' before initialization. The reason is that the variable is declared using let (not hoisted), so accessing it from the code above is forbidden.

Input code

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

@Table({
  tableName: 'chat_messages',
})
export class ChatMessage extends ModelBase<ChatMessage> {
  @AllowNull(false)
  @Column({
    field: 'text',
  })
  text: string;
}

Config

{
  "jsc": {
    "parser": {
      "syntax": "typescript",
      "tsx": false,
      "decorators": true,
    },
    "target": "es2021",
    "transform": {
      "legacyDecorator": false,
      "decoratorMetadata": true
    },
    "loose": false,
    "externalHelpers": false,
    "keepClassNames": true,
    "baseUrl": "./src",
    "paths": {
      "@/*": [
        "./*"
      ]
    }
  },
  "module": {
    "type": "commonjs"
  },
  "sourceMaps": true,
  "minify": false,
  "isModule": true
}

Playground link (or link to the minimal reproduction)

https://play.swc.rs/?version=1.4.11&code=H4sIAAAAAAAAA02OwQ6CMBBE7%2F2KvQEJ%2FgAYg3qGk3dTYcEmW4rdElHDv9uWxHjb3ZmdN0pPxjr4CICzoVmPOVzkjTCHI5F5NjNRLlbordGQMD5mJPXGnXtNyK1Vk0tKIar4koYQF6ZGaiwgae%2FSXTUyywE58TGZwCXiWpLMcPZ6vcmAi8OxY6hNh3SSjPs%2F9RD7Vb9GaS%2BJMQu3rXREA%2FQKqfNg59M8D2ANnrAVwM6qcSjFKr54bfeu8wAAAA%3D%3D&config=H4sIAAAAAAAAA3VRPU%2FDQAzd%2Bysijwi10JEJCQaWsDEhBnNxSsp9yXakRlX%2FO3dpLk0Gprv33tnv2XfeVBUcxcBTdU7XBCKyEM84MTJ4xVNiQIdIYriLCvdFVclSi1Zo5hoygVEDS5KU%2B0m5XA9Q5ANpbkiyf9g%2FQuEZvbSB3dLd0gHN8Fo6%2Fu9Vk2KDipPlytGGILQuBTopsUf7RjbSmHSp%2FhLFF4si7%2BhoPcaof6PQB9s8xHYnbMoMEfVHlvmfd3cJft4qt4mY0Nc15GYKCi40vaXbX%2BR9ZwcTnAv%2BKDC%2FlNCzoRrjMhq4znftsJwEOqlL03Erlz%2FvHLIU8gEAAA%3D%3D

SWC Info output

Operating System:
    Platform: darwin
    Arch: arm64
    Machine Type: arm64
    Version: Darwin Kernel Version 23.4.0: Wed Feb 21 21:44:43 PST 2024; root:xnu-10063.101.15~2/RELEASE_ARM64_T6000
    CPU: (8 cores)
        Models: Apple M1 Pro

Binaries:
    Node: 20.11.0
    npm: 10.2.4
    Yarn: N/A
    pnpm: N/A

Relevant Packages:
    @swc/core: 1.4.11
    @swc/helpers: N/A
    @swc/types: 0.1.6
    typescript: 4.3.2

SWC Config:
    output: N/A
    .swcrc path: N/A

Next.js info:
    output: N/A

Expected behavior

"use strict";
Object.defineProperty(exports, "__esModule", {
    value: true
});
Object.defineProperty(exports, "ChatMessage", {
    enumerable: true,
    get: function() {
        return ChatMessage;
    }
});

...

var ChatMessage = class ChatMessage extends ModelBase {
    constructor(...args){
        super(...args);
        _define_property(this, "text", void 0);
    }
};

or to define properties at the end of a file.

Actual behavior

"use strict";
Object.defineProperty(exports, "__esModule", {
    value: true
});
Object.defineProperty(exports, "ChatMessage", {
    enumerable: true,
    get: function() {
        return ChatMessage;
    }
});

...

let ChatMessage = class ChatMessage extends ModelBase {
    constructor(...args){
        super(...args);
        _define_property(this, "text", void 0);
    }
};

Version

1.4.11

Additional context

No response

[kdy1]

I think you have cyclic imports.
Usage of let is correct here

[kdy1]

#7435

[sergii-nosachenko]

@kdy1 Thanks, it was circular deps in Sequalize models.
This thread has helped me a lot to understand how to fix it.

[swc-bot]

This closed issue has been automatically locked because it had no new activity for a month. If you are running into a similar issue, please create a new issue with the steps to reproduce. Thank you.