fix: fix source map line number incorrect (#107)

修复跑单测时的堆栈行数及列数错误问题。

### 原因

espower-typescript 里会在 ts 的 sourcemap 基础上再加上 power-assert 的 sourcemap，因为 power-assert 会对源码做处理，然后会返回一个新的 code + sourcemap

然后 ts-node 里面自己内置了 source-map-support ，然后在 source-map-support 拿 code 的时候命中了 ts-node 的缓存 ( https://github.com/TypeStrong/ts-node/blob/master/src/index.ts#L218 )，拿到的是 ts-node 编译后的源码，而不是上面 espower-typescript 处理返回的...

所以导致 source-map-support 在实际处理 source map 映射的时候，code 是 power-assert 编译后的代码，sourceMap 却是 ts 的 sourceMap....就导致了这个问题。

### 解决方案

在 egg-bin test 的时候，由 egg-bin 来注册 source-map-support，缓存解析后的代码并且传给 sourceMapSupport。

---


Fix bug that error stack gives incorrect line number and column number in unit testing.

### Reason

`espower-typescript` combines the sourceMap of `ts-node` and `power-assert` and return a new sourceMap for supporting `power-assert`. But `source-map-support` receives old sourceMap when handling the code because `ts-node` cache its sourceMap in `retrieveFile` method: https://github.com/TypeStrong/ts-node/blob/master/src/index.ts#L218

```typescript
// Install source map support and read from memory cache.
sourceMapSupport.install({
  environment: 'node',
  retrieveFile: function (path) {
      return memoryCache.outputs[path];
  }
});
```

### Solution

Overwriting the `retrieveFile` method of `source-map-support` in `egg-bin test` to return a correct sourceMap for code.

power-assert-js/espower-typescript#54

.gitignore

@@ -11,11 +11,13 @@ test/fixtures/ts/node_modules/aliyun-egg/
 !test/fixtures/test-files-glob/**
 !test/fixtures/test-files-stack/node_modules/
 !test/fixtures/example/node_modules/
+!test/fixtures/example-ts-error-stack/node_modules/
 
 
 **/run/*.json
 .tmp
 .vscode
+.cache
 *.log
 package-lock.json
 .nyc_output

lib/cmd/test.js

@@ -105,6 +105,9 @@ class TestCommand extends Command {
     if (testArgv.typescript) {
       // remove ts-node in context getter on top.
       requireArr.push(require.resolve('espower-typescript/guess'));
+
+      // use to correct sourceMap mapping
+      requireArr.push(path.resolve(__dirname, '../correct-source-map'));
     }
 
     testArgv.require = requireArr;

lib/correct-source-map.js

@@ -0,0 +1,55 @@
+/**
+ * Only works in test/cov command with `espower-typescript`.
+ *
+ * Fix bug that error stack gives incorrect line number and column number in unit testing.
+ *
+ * ### Reason
+ *
+ * `espower-typescript` combines the sourceMap of `ts-node` and `power-assert` and return a new sourceMap
+ *  for supporting `power-assert`. But `source-map-support` receives old sourceMap when handling the code because
+ *  `ts-node` cache its sourceMap in `retrieveFile` method: https://github.com/TypeStrong/ts-node/blob/master/src/index.ts#L218
+ *
+ * ```typescript
+ * // Install source map support and read from memory cache.
+ * sourceMapSupport.install({
+ *   environment: 'node',
+ *   retrieveFile: function (path) {
+ *       return memoryCache.outputs[path];
+ *     }
+ * });
+ * ```
+ *
+ * ### Solution
+ *
+ * Overwriting the `retrieveFile` method of `source-map-support` in `egg-bin test` to return a correct sourceMap for code.
+ *
+ *
+ * https://github.com/eggjs/egg-bin/pull/107
+ * https://github.com/power-assert-js/espower-typescript/issues/54
+ *
+ */
+
+'use strict';
+
+const sourceMapSupport = require('source-map-support');
+const cacheMap = {};
+const extensions = [ '.ts', '.tsx' ];
+
+sourceMapSupport.install({
+  environment: 'node',
+  retrieveFile(path) {
+    return cacheMap[path];
+  },
+});
+
+for (const ext of extensions) {
+  const originalExtension = require.extensions[ext];
+  require.extensions[ext] = (module, filePath) => {
+    const originalCompile = module._compile;
+    module._compile = function(code, filePath) {
+      cacheMap[filePath] = code;
+      return originalCompile.call(this, code, filePath);
+    };
+    return originalExtension(module, filePath);
+  };
+}

package.json

@@ -19,6 +19,7 @@
     "globby": "^8.0.1",
     "inspector-proxy": "^1.2.1",
     "intelli-espower-loader": "^1.0.1",
+    "source-map-support": "^0.5.6",
     "mocha": "^5.2.0",
     "mz-modules": "^2.1.0",
     "nyc": "^12.0.2",

test/fixtures/example-ts-error-stack/app.ts

@@ -0,0 +1,9 @@
+export default function() {
+  // placeholder comments
+  // placeholder comments
+  // placeholder comments
+  // placeholder comments
+  if (process.env.THROW_ERROR === 'true') {
+    throw new Error('throw error');
+  }
+}

test/fixtures/example-ts-error-stack/config/config.default.ts

@@ -0,0 +1,7 @@
+'use strict';
+
+export default () => {
+  const config = {} as any;
+  config.keys = '123456';
+  return config;
+};

test/fixtures/example-ts-error-stack/package.json

@@ -0,0 +1,6 @@
+{
+  "name": "example-ts-error-stack",
+  "egg": {
+    "typescript": true
+  }
+}

test/fixtures/example-ts-error-stack/test/index.test.ts

@@ -0,0 +1,16 @@
+'use strict';
+
+// import * as assert from 'assert';
+
+describe('test/index.test.ts', () => {
+  // placeholder comments
+  it('should throw error', async () => {
+    throw new Error('error');
+  });
+
+  // placeholder comments
+  it('should assert', async () => {
+    const obj = { key: '111' };
+    assert(obj.key === '222');
+  });
+});

test/fixtures/example-ts-error-stack/tsconfig.json

@@ -0,0 +1,19 @@
+{
+  "compilerOptions": {
+    "target": "es2017",
+    "module": "commonjs",
+    "strict": true,
+    "noImplicitAny": false,
+    "moduleResolution": "node",
+    "experimentalDecorators": true,
+    "emitDecoratorMetadata": true,
+    "pretty": true,
+    "noUnusedLocals": true,
+    "noUnusedParameters": true,
+    "noFallthroughCasesInSwitch": true,
+    "skipLibCheck": true,
+    "skipDefaultLibCheck": true,
+    "inlineSourceMap": true,
+    "importHelpers": true
+  },
+}

test/ts.test.js

@@ -74,6 +74,44 @@ describe('test/ts.test.js', () => {
     });
   });
 
+  describe('error stacks', () => {
+    if (process.env.EGG_VERSION && process.env.EGG_VERSION === '1') {
+      console.log('skip egg@1');
+      return;
+    }
+
+    before(() => {
+      cwd = path.join(__dirname, './fixtures/example-ts-error-stack');
+    });
+
+    it('should correct error stack line number in starting app', () => {
+      mm(process.env, 'THROW_ERROR', 'true');
+      return coffee.fork(eggBin, [ 'dev' ], { cwd })
+        // .debug()
+        .expect('stderr', /Error: throw error/)
+        .expect('stderr', /at \w+ \(.+app\.ts:7:11\)/)
+        .end();
+    });
+
+    it('should correct error stack line number in testing app', () => {
+      return coffee.fork(eggBin, [ 'test' ], { cwd })
+        // .debug()
+        .expect('stdout', /error/)
+        .expect('stdout', /at Context\.it .+index\.test\.ts:8:11\)/)
+        .expect('stdout', /at Context\.it .+index\.test\.ts:14:5\)/)
+        .end();
+    });
+
+    it('should correct error stack line number in covering app', () => {
+      return coffee.fork(eggBin, [ 'test' ], { cwd })
+        // .debug()
+        .expect('stdout', /error/)
+        .expect('stdout', /at Context\.it .+index\.test\.ts:8:11\)/)
+        .expect('stdout', /at Context\.it .+index\.test\.ts:14:5\)/)
+        .end();
+    });
+  });
+
   describe('egg.typescript = true', () => {
     if (process.env.EGG_VERSION && process.env.EGG_VERSION === '1') {
       console.log('skip egg@1');