ReferenceError：全局未使用 web3 定义

Posted 2023-03-13

【中文标题】ReferenceError：全局未使用 web3 定义

【英文标题】：ReferenceError: global is not defined with web3

【发布时间】：2019-12-13 03:38:12

【问题描述】：

一段时间以来，我一直在尝试将 Web3 安装到我的 Ionic v4 项目中。当我为项目服务时，它不断抛出错误。我收到一条错误消息，指出 Reference Error: global is not defined。

开始一个新的 Ionic 项目 安装 web3：npm install --save web3 安装节点类型：npm install --save-dev @types/node 编辑一些代码以访问 web3：

import  Component  from '@angular/core';
import  Web3  from 'web3'; 

@Component(
  selector: 'app-home',
  templateUrl: 'home.page.html',
  styleUrls: ['home.page.scss'],
)
export class HomePage 

  web3 = new Web3(new Web3.providers.HttpProvider('https://rinkeby.infura.io/v3/apikey...'));

  constructor() 

  test()
    console.log(this.web3);
  

运行离子服务 编译成功，但在谷歌浏览器的控制台中出现这样的错误

core.js:9110 ERROR Error: Uncaught (in promise): ReferenceError: global is not defined
ReferenceError: global is not defined
    at Object../node_modules/stream-http/lib/capability.js (capability.js:1)
    at __webpack_require__ (bootstrap:84)
    at Object../node_modules/stream-http/lib/request.js (request.js:1)
    at __webpack_require__ (bootstrap:84)
    at Object../node_modules/stream-http/index.js (index.js:1)
    at __webpack_require__ (bootstrap:84)
    at Object../node_modules/xhr2-cookies/dist/xml-http-request.js (xml-http-request.js:21)
    at __webpack_require__ (bootstrap:84)
    at Object../node_modules/xhr2-cookies/dist/index.js (index.js:6)
    at __webpack_require__ (bootstrap:84)
    at resolvePromise (zone-evergreen.js:797)
    at resolvePromise (zone-evergreen.js:754)
    at zone-evergreen.js:858
    at ZoneDelegate.invokeTask (zone-evergreen.js:391)
    at Object.onInvokeTask (core.js:34182)
    at ZoneDelegate.invokeTask (zone-evergreen.js:390)
    at Zone.runTask (zone-evergreen.js:168)
    at drainMicroTaskQueue (zone-evergreen.js:559)

package.json

  "name": "my-app",
  "version": "0.0.1",
  "author": "Ionic Framework",
  "homepage": "https://ionicframework.com/",
  "scripts": 
    "ng": "ng",
    "start": "ng serve",
    "build": "ng build",
    "test": "ng test",
    "lint": "ng lint",
    "e2e": "ng e2e"
  ,
  "private": true,
  "dependencies": 
    "@angular/common": "~8.1.2",
    "@angular/compiler": "~8.1.2",
    "@angular/core": "~8.1.2",
    "@angular/forms": "~8.1.2",
    "@angular/platform-browser": "~8.1.2",
    "@angular/platform-browser-dynamic": "~8.1.2",
    "@angular/router": "~8.1.2",
    "@ionic-native/core": "^5.0.0",
    "@ionic-native/splash-screen": "^5.0.0",
    "@ionic-native/status-bar": "^5.0.0",
    "@ionic/angular": "^4.7.1",
    "core-js": "^2.5.4",
    "rxjs": "~6.5.1",
    "tslib": "^1.9.0",
    "web3": "^1.2.0",
    "zone.js": "~0.9.1"
  ,
  "devDependencies": 
    "@angular-devkit/architect": "~0.801.2",
    "@angular-devkit/build-angular": "~0.801.2",
    "@angular-devkit/core": "~8.1.2",
    "@angular-devkit/schematics": "~8.1.2",
    "@angular/cli": "~8.1.2",
    "@angular/compiler": "~8.1.2",
    "@angular/compiler-cli": "~8.1.2",
    "@angular/language-service": "~8.1.2",
    "@ionic/angular-toolkit": "~2.0.0",
    "@types/jasmine": "~3.3.8",
    "@types/jasminewd2": "~2.0.3",
    "@types/node": "^8.9.5",
    "codelyzer": "^5.0.0",
    "jasmine-core": "~3.4.0",
    "jasmine-spec-reporter": "~4.2.1",
    "karma": "~4.1.0",
    "karma-chrome-launcher": "~2.2.0",
    "karma-coverage-istanbul-reporter": "~2.0.1",
    "karma-jasmine": "~2.0.1",
    "karma-jasmine-html-reporter": "^1.4.0",
    "protractor": "~5.4.0",
    "ts-node": "~7.0.0",
    "tslint": "~5.15.0",
    "typescript": "~3.4.3"
  ,
  "description": "An Ionic project"

我在这里找到了一个建议https://github.com/ethereum/web3.js/issues/2260#issuecomment-458519127。 我遵循了每一步，但我也遇到了同样的错误。

如何将 web3 导入 Ionic 项目？

【参考方案1】：

不确定 ionic 是否有自己的 polyfill，但您可以将其添加到您的 polyfill 中

(window as any).global = window;
if (global === undefined) 
   var global = window;

【讨论】：

你能提供关于 polyfill 的上下文吗？这对于 javascript 前端的新手来说并不清楚。