react_dom_development 在 Deno React 项目中未定义

Question

我想尝试一下 Deno，所以我决定制作一个简单的单页 React 应用程序。但是，当我尝试从 CDN 拉入 ReactDOM 时，出现控制台错误：react_dom_development_js_2 is undefined。

我想这是怎么回事，它无法解析 ReactDOM CDN，但我可以从我的浏览器访问它？我也尝试用浏览器解析的内容替换它 (https://unpkg.com/react-dom@16.13.1/umd/react-dom.development.js)，但我仍然遇到同样的错误。也许我用错了deno bundle？

index.jsx

import { React } from "https://unpkg.com/react@16/umd/react.development.js";
import { ReactDOM } from "https://unpkg.com/react-dom@16/umd/react-dom.development.js";

ReactDOM.render(<p>Hello</p>, document.findElementById("app"));

index.html

<html>
  <head>
    <title>Test with Deno</title>
  </head>
  <body>

    <div id="app"></div>
    <script src="index.bundle.js"></script>
  </body>
</html>

我运行 deno bundle index.jsx index.bundle.js 创建我的包，

index.bundle.js

// Copyright 2018-2020 the Deno authors. All rights reserved. MIT license.

// This is a specialised implementation of a System module loader.

// @ts-nocheck
/* eslint-disable */
let System, __instantiateAsync, __instantiate;

(() => {
  const r = new Map();

  System = {
    register(id, d, f) {
      r.set(id, { d, f, exp: {} });
    },
  };

  async function dI(mid, src) {
    let id = mid.replace(/\.\w+$/i, "");
    if (id.includes("./")) {
      const [o, ...ia] = id.split("/").reverse(),
        [, ...sa] = src.split("/").reverse(),
        oa = [o];
      let s = 0,
        i;
      while ((i = ia.shift())) {
        if (i === "..") s++;
        else if (i === ".") break;
        else oa.push(i);
      }
      if (s < sa.length) oa.push(...sa.slice(s));
      id = oa.reverse().join("/");
    }
    return r.has(id) ? gExpA(id) : import(mid);
  }

  function gC(id, main) {
    return {
      id,
      import: (m) => dI(m, id),
      meta: { url: id, main },
    };
  }

  function gE(exp) {
    return (id, v) => {
      v = typeof id === "string" ? { [id]: v } : id;
      for (const [id, value] of Object.entries(v)) {
        Object.defineProperty(exp, id, {
          value,
          writable: true,
          enumerable: true,
        });
      }
    };
  }

  function rF(main) {
    for (const [id, m] of r.entries()) {
      const { f, exp } = m;
      const { execute: e, setters: s } = f(gE(exp), gC(id, id === main));
      delete m.f;
      m.e = e;
      m.s = s;
    }
  }

  async function gExpA(id) {
    if (!r.has(id)) return;
    const m = r.get(id);
    if (m.s) {
      const { d, e, s } = m;
      delete m.s;
      delete m.e;
      for (let i = 0; i < s.length; i++) s[i](await gExpA(d[i]));
      const r = e();
      if (r) await r;
    }
    return m.exp;
  }

  function gExp(id) {
    if (!r.has(id)) return;
    const m = r.get(id);
    if (m.s) {
      const { d, e, s } = m;
      delete m.s;
      delete m.e;
      for (let i = 0; i < s.length; i++) s[i](gExp(d[i]));
      e();
    }
    return m.exp;
  }

  __instantiateAsync = async (m) => {
    System = __instantiateAsync = __instantiate = undefined;
    rF(m);
    return gExpA(m);
  };

  __instantiate = (m) => {
    System = __instantiateAsync = __instantiate = undefined;
    rF(m);
    return gExp(m);
  };
})();

System.register(
  "index",
  [
    "https://unpkg.com/react@16/umd/react.development.js",
    "https://unpkg.com/react-dom@16/umd/react-dom.development.js",
  ],
  function (exports_1, context_1) {
    "use strict";
    var react_development_js_1, react_dom_development_js_1;
    var __moduleName = context_1 && context_1.id;
    return {
      setters: [
        function (react_development_js_1_1) {
          react_development_js_1 = react_development_js_1_1;
        },
        function (react_dom_development_js_1_1) {
          react_dom_development_js_1 = react_dom_development_js_1_1;
        },
      ],
      execute: function () {
        react_dom_development_js_1.ReactDOM.render(
          react_development_js_1.React.createElement("p", null, "Hello"),
          document.findElementById("app"),
        );
      },
    };
  },
);

__instantiate("index");

Answer 1

TypeScript 不允许从 html 导入或以文件扩展名结尾。所以现在你可以使用 // @ts-ignore 忽略它们，这将允许 deno 工作。

deno 有一个 visual studio 代码扩展，但在撰写本文时它似乎有点不稳定。如果以及当它正常工作时，您将能够通过在项目的根目录中定义一个设置文件夹来配置 deno 在每个项目的基础上工作，例如.vscode/settings.json.

{
  "deno.enable": true
}

Answer 2

这里的问题是由于典型的 React 和 ReactDOM 包被编写为 commonJS 包。

Deno 默认要求所有模块都使用 ES 模块 (ESM) 编写。 https://github.com/pikapkg/react is a build of React and ReactDOM that use ESM, so they should be importable in Deno. link with CDN

deno 中有一个标准库模块，可让您使用 commonJS 模块，但您需要小心使用它们，尤其是当它们需要特定于节点的功能时：https://deno.land/std/node#commonjs-module-loading

react_dom_development 在 Deno React 项目中未定义

react_dom_development is undefined in Deno React project

javascript

reactjs

deno