通过 tsconfig 路径导入时代码运行但 instanceof 失败

Question

这里有些奇怪的行为。我正在使用 Mocha 编写单元测试，它调用 Class 的静态方法，将 LatLng 转换为传单 L.LatLng 对象。在测试结束时，我正在检查返回的对象是否确实是 L.LatLng 的实例。令人惊讶的是，测试失败了，即使它确实是 L.LatLng 的一个实例。摸索了几个小时后，我能够将问题缩小到以下几点。如果我通过 tsconfig 路径参数

导入转换器 class

import { LeafletConverter } from '@maps/leaflet/leaflet-converter';

然后测试失败。但是如果我通过相对路径导入它：

import { LeafletConverter } from '../../../app/maps/leaflet/leaflet-converter';

然后测试通过没有错误。问题是，这里发生了什么，有什么方法可以保持“@maps/...”导入样式吗？

版本：

$ tsc --version
Version 3.6.3

VSCode 1.39.2

测试文件：

    import { expect } from 'chai';
    import 'mocha';
    import L from "leaflet";
    import { LeafletConverter as DirectLeafletConverter } from '../../../app/maps/leaflet/leaflet-converter';
    import { LeafletConverter } from '@maps/leaflet/leaflet-converter';
    import { LatLng } from '@maps/lat-lng';


    describe.only('maps/leaflet/asdf', () => {


        it('tsconfig path import - this test fails', () => {
            const leafletll = LeafletConverter.toLeafletLatLng(new LatLng(1,2));
            const test = leafletll instanceof L.LatLng;
            expect(test).to.be.true;
        });

        it('direct import - this test passes', () => {
            const leafletll = DirectLeafletConverter.toLeafletLatLng(new LatLng(1,2));
            const test = leafletll instanceof L.LatLng;
            expect(test).to.be.true;
        });


    });

LeafletConverter.ts

    import { LatLng } from "@maps/lat-lng";
    import L from "leaflet";
    import { LatLngBounds } from "@maps/lat-lng-bounds";

    export abstract class LeafletConverter {
        private constructor(){}

...


        public static toLeafletLatLng(latLng: LatLng): L.LatLng  {
            let result: L.LatLng = null;

            if(LatLng.isValid(latLng)) {
                result = L.latLng(latLng.lat,latLng.lng);
            }

            return result;
        }

...

    }

测试命令&输出：

$ "C:\Program Files\nodejs\node.exe" --inspect-brk=22915 node_modules\mocha\bin\_mocha -r ts-node/register -r tsconfig-paths/register --timeout 30000 --colors C:\Users\Asdf\tmp\rm.js\group
test/**/*.test.ts
Debugger listening on ws://127.0.0.1:22915/e1b8ec38-90ac-41dd-aded-c2c20e2ffa28
For help, see: https://nodejs.org/en/docs/inspector
Debugger attached.


  maps/leaflet/asdf
    1) tsconfig path import
    √ direct import        


  1 passing (14ms)
  1 failing

  1) maps/leaflet/asdf
       tsconfig path import:

      AssertionError: expected false to be true
      + expected - actual

      -false
      +true

      at Context.<anonymous> (C:\Users\Asdf\tmp\rm.js\group-clusterer\src\test\maps\leaflet\asdf.test.ts:16:27)



Waiting for the debugger to disconnect...

package.json

{
  "name": "typescript-webpack-seed-project",
  "version": "0.0.1",
  "description": "",
  "main": "index.js",
  "scripts": {
    "test": "mocha -r ts-node/register -r tsconfig-paths/register src/test/**/*.test.ts",
    "compile": "npx tsc",
    "cc": "npx tsc -w",
    "build": "webpack"
  },
  "author": "",
  "license": "ISC",
  "devDependencies": {
    "@types/chai": "^4.2.3",
    "@types/googlemaps": "^3.38.0",
    "@types/leaflet": "^1.5.5",
    "@types/mocha": "^5.2.7",
    "@types/node": "^12.12.5",
    "@types/q": "^1.5.2",
    "@types/rbush": "^2.0.3",
    "chai": "^4.2.0",
    "jsdom": "15.2.1",
    "jsdom-global": "3.0.2",
    "leaflet": "^1.5.1",
    "mocha": "^6.2.1",
    "ts-loader": "^6.2.0",
    "ts-node": "^8.4.1",
    "tsconfig-paths": "^3.9.0",
    "tsconfig-paths-webpack-plugin": "^3.2.0",
    "tslint": "^5.20.0",
    "typescript": "^3.6.3",
    "uglifyjs-webpack-plugin": "^2.2.0",
    "webpack": "^4.41.2",
    "webpack-cli": "^3.3.9"
  },
  "dependencies": {
    "q": "^1.5.1",
    "rbush": "^3.0.1"
  }
}

Answer 1

找到解决办法。问题的根本原因是 mocha 命令行命令中 ts 文件的绝对路径。当我修改这个...

$ "C:\Program Files\nodejs\node.exe" --inspect-brk=22915 node_modules\mocha\bin\_mocha -r ts-node/register -r tsconfig-paths/register --timeout 30000 --colors C:\Users\Asdf\tmp\rm.js\group-clusterer/src/test/**/*.test.ts

对此...

$ "C:\Program Files\nodejs\node.exe" --inspect-brk=22915 node_modules\mocha\bin\_mocha -r ts-node/register -r tsconfig-paths/register --timeout 30000 --colors src/test/**/*.test.ts

然后一切正常。这是为什么呢？我不知道...

通过 tsconfig 路径导入时代码运行但 instanceof 失败

code runs but instanceof failes when importing via tsconfig path

import

instanceof

mocha.js

typescript