Decorators support inconsistent with Typescript #8864
Description
Bug Report
I was trying to port build pipeline (webpack) from ts-loader to babel-loader.
I am using decorator (for redux action types) implementation bellow.
Current Behavior
My input code works just fine with typescript. However using babel, prototype in actionClass in my decorator is undefined. I also tried various modifications (omit prototype and set type directly on actionClass) but all failed. I was simply unable to set type on the base class with decorator.
// Babel console.log(actionClass);
Descriptor {kind: "class", elements: Array(0), Symbol(Symbol.toStringTag): "Descriptor"}
Input Code
abstract class Action {
public type: string;
constructor() {
this.type = this.type;
}
}
export interface ActionClass<T extends Action> {
prototype: T;
}
export function typeName(name: string): <T extends Action>(actionClass: ActionClass<T>) => void {
return actionClass => {
actionClass.prototype.type = name;
};
}
// Usage :
export interface TestActionPayload {
sample: string;
}
@typeName('TEST_ACTION')
export class TestAction extends Action {
constructor(public payload: TestActionPayload) {
super(payload);
}
}
Expected behavior/code
It is partly unclear to me if this is a bug, or problem on my end. However, one way or another, I am expecting to be able to set properties on base class with decorators. Currently I can't.
// Typescript console.log(actionClass);
ƒ TestAction(payload) {
var _this = _super.call(this, payload) || this;
_this.payload = payload;
return _this;
}
Babel Configuration (.babelrc, package.json, cli command)
options: {
cacheDirectory: true,
babelrc: false,
presets: [
[
"@babel/preset-env",
{ targets: { browsers: "last 2 versions" } } // or whatever your project requires
],
"@babel/preset-typescript",
"@babel/preset-react"
],
plugins: [
["@babel/plugin-proposal-decorators", { decoratorsBeforeExport: true }],
["@babel/plugin-proposal-class-properties", { loose: true }],
"@babel/plugin-syntax-dynamic-import",
"react-hot-loader/babel"
]
}
Environment
- Babel version(s): [7.1.2]
- Node/npm version: [Node 9.5.0/npm 6.4.1]
- OS: [Windows 10]
- Monorepo [no]
- How you are using Babel: [
loader]
Possible Solution
Additional context/Screenshots
Add any other context about the problem here. If applicable, add screenshots to help explain.