# 五.配置跨域问题
# 1.安装
package.json
{
"name": "5.cors",
"version": "1.0.0",
"description": "",
"main": "index.js",
"scripts": {
"test": "echo \"Error: no test specified\" && exit 1",
"dev": "webpack-dev-server --open --mode development"
},
"keywords": [],
"author": "",
"license": "ISC",
"devDependencies": {
"html-webpack-plugin": "^3.2.0",
"webpack": "^4.29.6",
"webpack-cli": "^3.3.0",
"webpack-dev-server": "^3.2.1"
}
}
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# 2.文件
# 2.1 src/index.js
let xhr = new XMLHttpRequest()
xhr.open("GET", "/api/user", true)
xhr.onload = function() {
console.log(xhr.response)
}
xhr.send()
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# 2.2 index.html
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8" />
<meta name="viewport" content="width=device-width, initial-scale=1.0" />
<meta http-equiv="X-UA-Compatible" content="ie=edge" />
<title>webpack跨域</title>
</head>
<body></body>
</html>
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# 2.3 用 express 写一个服务端
server.js
let express = require("express")
let app = express()
app.get("/user", (req, res) => {
res.json({ name: "这是我" })
})
app.listen(3000)
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# 3.配置
# 3.1 webpack.config.js
第一种：配置本地代理实现跨域
const path = require("path")
let HtmlWebpackPlugin = require("html-webpack-plugin")
module.exports = {
mode: "development",
entry: {
home: "./src/index.js",
},
devServer: {
proxy: {
"/api": {
target: "http://localhost:3000",
pathRewrite: { "/api": "" },
},
},
},
output: {
filename: "[name].js",
path: path.resolve(__dirname, "dist"),
},
plugins: [
new HtmlWebpackPlugin({
template: "./index.html",
filename: "index.html",
}),
],
}
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第二种：模拟数据
before(app) {
app.get("/api/user", (req, res) => {
res.json({ name: "before" });
});
}
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第三种：修改 index.js 中请求地址
let xhr = new XMLHttpRequest()
xhr.open("GET", "/user", true)
xhr.onload = function() {
console.log(xhr.response)
}
xhr.send()
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打开http://localhost:3000/