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{"@context":"https://schema.org","@type":"DiscussionForumPosting","headline":"Functions wrapped in `__importDefault` with allowSyntheticDefaultImports emit incorrect function calls","articleBody":"The following code:\r\n\r\n```ts\r\nimport allSettled from \"promise.allsettled\";\r\n\r\nconst resolved = Promise.resolve(42);\r\nconst rejected = Promise.reject(-1);\r\n\r\nallSettled([resolved, rejected]).then(results => {\r\n  console.log(results);\r\n});\r\n```\r\n\r\nIs transpiled into the following JS with `esModuleInterop` & `allowSyntheticDefaultImports`:\r\n\r\n```js\r\n\"use strict\";\r\nvar __importDefault =\r\n  (this && this.__importDefault) ||\r\n  function(mod) {\r\n    return mod && mod.__esModule ? mod : { default: mod };\r\n  };\r\nObject.defineProperty(exports, \"__esModule\", { value: true });\r\nconst promise_allsettled_1 = __importDefault(require(\"promise.allsettled\"));\r\nconst resolved = Promise.resolve(42);\r\nconst rejected = Promise.reject(-1);\r\npromise_allsettled_1.default([resolved, rejected]).then(results => {\r\n  console.log(results);\r\n});\r\n```\r\n\r\nFull `tsconfig.json`:\r\n\r\n```js\r\n{\r\n  \"compilerOptions\": {\r\n    \"target\": \"es2018\",\r\n    \"module\": \"commonjs\",\r\n    \"strict\": true,\r\n    \"allowSyntheticDefaultImports\": true,\r\n    \"esModuleInterop\": true,\r\n  },\r\n  \"include\": [\r\n    \"src\"\r\n  ]\r\n}\r\n```\r\n\r\n([CodeSandbox](https://codesandbox.io/s/inspiring-lewin-eyt6r).)\r\n\r\nExecuting this code leads to:\r\n\r\n```\r\nTypeError: #\u003cObject> is not a constructor\r\n    at Object.resolve (\u003canonymous>)\r\n    at Object.PromiseResolve (/sandbox/node_modules/es-abstract/es2018.js:160:10)\r\n    at /sandbox/node_modules/promise.allsettled/implementation.js:26:24\r\n    at Function.from (\u003canonymous>)\r\n    at Object.allSettled (/sandbox/node_modules/promise.allsettled/implementation.js:19:22)\r\n    at Object.allSettled [as default] (/sandbox/node_modules/promise.allsettled/index.js:16:9)\r\n    at Object.\u003canonymous> (/sandbox/src/demo.ts:6:11)\r\n    at Module._compile (internal/modules/cjs/loader.js:776:30)\r\n    at Module.m._compile (/sandbox/node_modules/ts-node/src/index.ts:536:23)\r\n    at Module._extensions..js (internal/modules/cjs/loader.js:787:10)\r\n```\r\n\r\nThat is because the promise.allsettled package handles `this` according to the spec, see https://github.com/es-shims/Promise.allSettled/issues/5. The author of that library is @ljharb who will have deeper understanding of the specifics than I do. (Also, thanks for nudging me to report this issue!)\r\n\r\nThe problem is most likely the emitted function call, which looks like this:\r\n\r\n```js\r\npromise_allsettled_1.default([resolved, rejected]).then(results => {\r\n  console.log(results);\r\n});\r\n```\r\n\r\nIn comparison, Babel + TS emits this (which works):\r\n\r\n```js\r\n(0, _promise.default)([resolved, rejected]).then(function (results) {\r\n  console.log(results);\r\n});\r\n```\r\n\r\n[Babel playground](https://babeljs.io/en/repl#?babili=false&browsers=&build=&builtIns=false&spec=false&loose=false&code_lz=JYWwDg9gTgLgBAQwDZIMoFMYyegJnAMyghDgHIxiRgBndAOmSTqx1zIG4AoLgYwgB2NeFHQ0ISAG544AXjgAFKrQajxU9AAoALACYAlN35CR6AFbpeMGfKUkV9URauaAtAEZDPJhlZ5NANpqEtK4ADRwTpbWuAC6-vQwABboAppqAK5IMDRyAHxwAN5ccHDG6gxIEADm6WJZOV4AvoZAA&debug=false&forceAllTransforms=false&shippedProposals=false&circleciRepo=&evaluate=false&fileSize=false&timeTravel=false&sourceType=module&lineWrap=true&presets=es2015%2Creact%2Cstage-2%2Ctypescript&prettier=false&targets=&version=7.7.4&externalPlugins=).\r\n\r\n**TypeScript Version:**  3.7.2\r\n\r\n**Search Terms:** `esModuleInterop`, `allowSyntheticDefaultImports`, emit, transpile, downlevel compile, ES Modules, default, wrapper, Node.js, module.","author":{"url":"https://github.com/borekb","@type":"Person","name":"borekb"},"datePublished":"2019-11-29T10:31:28Z","url":"https://github.com/microsoft/TypeScript/issues/35420"}