Injectable decorator is still required

[ffMathy]

Is there an existing issue for this?

• I have searched the existing issues

Current behavior

In version 6.1.0, this release note was added:

injectable decorator is no longer required.

Can you detail how that works? Currently if I try to remove my @injectable() decorators on my classes, I get these errors everywhere:

Error while synchronizing SKU "01932c80-1010-743d-92c5-06c8887b2107" with error Error: Found unexpected missing metadata on type "SomeClass" at constructor indexes "0".
  
  Are you using @inject, @multiInject or @unmanaged decorators at those indexes?
  
  If you're using typescript and want to rely on auto injection, set "emitDecoratorMetadata" compiler option to true

Steps to reproduce

No response

Expected behavior

I expected Inversify to still work without that decorator on the class.

Possible solution

No response

Package version

6.1.4

Node.js version

23.0.0

In which operating systems have you tested?

• macOS
• Windows
• Linux

Stack trace

No response

Other

No response

[notaphplover]

Hey @ffMathy, I have been investigating the issue. Tbh, it seems @injectable will continue being mandatory.

The issue

Currently, injectable decorator should not be required. Metadata readers are prepared to fetch tsc metadata from design:paramtypes.

Unfortunatelly, it seems design:paramtypes is only included in the class metadata if and only if there's at least one class decorator applied to the class.

Having emitDecoratorMetadata set to true:

import 'reflect-metadata';
import { injectable } from 'inversify';

@injectable()
class B {
  readonly foo: string = 'foo';
}

@injectable()
class A {
  constructor(public readonly b: B) {}
}

is transpiled into

Object.defineProperty(exports, "__esModule", { value: true });
require("reflect-metadata");
const inversify_1 = require("inversify");
let B = class B {
    foo = 'foo';
};
B = __decorate([
    (0, inversify_1.injectable)()
], B);
let A = class A {
    b;
    constructor(b) {
        this.b = b;
    }
};
A = __decorate([
    (0, inversify_1.injectable)(),
    __metadata("design:paramtypes", [B])
], A);

If we remove the injectable decorator:

import 'reflect-metadata';

class B {
  readonly foo: string = 'foo';
}

class A {
  constructor(public readonly b: B) {}
}

It's transpiled into

Object.defineProperty(exports, "__esModule", { value: true });
require("reflect-metadata");
class B {
    foo = 'foo';
}
class A {
    b;
    constructor(b) {
        this.b = b;
    }
}

To sum it up, @injectable is required if you expect typescript metadata to be provided.

I'll update docs and the next version will have docs updated. Until that, I'll leave this issue open.