Decorators do not work, when targeting ES2022

[paulsmithkc]

🔎 Search Terms

decorator, target:ES2022, experimentalDecorators, emitDecoratorMetadata, TC39

🕗 Version & Regression Information

This changed between target:ES2021 and target:ES2022

⏯ Playground Link

https://github.com/paulsmithkc/typescript-decorators

💻 Code

tsconfig.json

{
  "compilerOptions": {
    "target": "ES2022",
    "module": "commonjs",
    "outDir": "dist",
    "declaration": true,
    "experimentalDecorators": true,
    "emitDecoratorMetadata": true
  },
  "include": ["src"],
  "exclude": ["node_modules", "dist"]
}

src/index.ts

function setting(defaultValue: string): any {
  function settingExperimental(target: unknown, property: string | symbol): void {
    console.log('settingExperimental', { defaultValue, target, property });
    target[property] = process.env[String(property)] || defaultValue;
    return;
  }
  function settingTC39(_target: unknown, context: ClassFieldDecoratorContext): () => string {
    return function (): string {
      console.log('settingTC39', { defaultValue, target: this, context, type });
      return process.env[String(context.name)] || defaultValue;
    };
  }
  return function (target: unknown, context: string | symbol | ClassFieldDecoratorContext) {
    if (typeof context !== 'object') {
      return settingExperimental(target, context);
    } else {
      return settingTC39(target, context);
    }
  };
}

console.log('CLASS DECLARATION.');
class Config1 {
  @setting('default_1') SETTING_ONE: string;
}
class Config2 extends Config1 {
  @setting('default_2') SETTING_TWO: string;
}

console.log('OBJECT INSTANTIATION.');
const configInstance = new Config2();
console.log({
  prototype1: Config1.prototype,
  prototype2: Config2.prototype,
  SETTING_ONE: configInstance.SETTING_ONE,
  SETTING_TWO: configInstance.SETTING_TWO,
});

if (!configInstance.SETTING_ONE) {
  throw new Error('SETTING_ONE NOT INITIALIZED');
}
if (!configInstance.SETTING_TWO) {
  throw new Error('SETTING_TWO NOT INITIALIZED');
}

console.log('DONE.');

run with:

tsc --project tsconfig.json && node dist/index.js

🙁 Actual behavior

When targeting ES2022:

• SETTING_ONE and SETTING_TWO are both undefined.

When targeting ES2021:

• SETTING_ONE and SETTING_TWO are populated as expected.

🙂 Expected behavior

When targeting an version of ECMA script:

• SETTING_ONE and SETTING_TWO are populated as expected.

Additional information about the issue

The generate code differs from ES2021 to ES2022, which is what is causing this issue.

ES2021

class Config1 {
}
class Config2 {
}

ES2022

class Config1 {
    SETTING_ONE;
}
class Config2 extends Config1 {
    SETTING_TWO;
}

[MartinJohns]

This is working as intended. See: https://www.typescriptlang.org/tsconfig/useDefineForClassFields.html

And also: #48814

[typescript-bot]

This issue has been marked as "Working as Intended" and has seen no recent activity. It has been automatically closed for house-keeping purposes.