打字稿删除（树木）我的文件/类

Question

Suppose a class adds itself to an other class as follows

bar.ts :

import { Foo } from './foo';

export class Bar {}

Foo.prop = Bar;

And file foo.ts

export class Foo {
    public static prop: any;
}

Now, if would like to use this in index.ts

import { Foo } from './foo';

console.log(Foo.prop); // -> undefined

It is undefined. It looks like that bar.ts is not used at all (probably tree shaking). So I can fix that as follows:

import { Foo } from './foo';
import { Bar } from './bar';

new Bar(); // trick!
console.log(Foo.prop); // -> Bar

Is there a way to tell typescript to include Bar anyway, because the solution I showed is ugly.

For completeness, here is my tsconfig.json

{
  "compilerOptions": {
    "module": "commonjs",
    "declaration": true,
    "sourceMap": true,
    "noImplicitAny": false,
    "removeComments": true,
    "emitDecoratorMetadata": true,
    "experimentalDecorators": true,
    "target": "es2017",
    "outDir": "./dist",
    "baseUrl": "./",
    "lib": ["es2017", "dom", "dom.iterable"]
  },
  "exclude": ["node_modules", "**/*.spec.ts", "dist"]
}

Answer 1

Foo.prop = Bar;

is what is causing the issue, you're doing this in Bar.ts, do this in Foo.ts, now when you create a new object of Foo in index.ts, tree shaking won't remove Bar.ts.

As a general rule, if you need to add a dependency to a class,always do that in the file where the class is defined (Foo.ts in this case)