我正在尝试在Babel 6上从头开始使用async/await，但我得到的是regeneratorRuntime没有定义。
.babelrc文件
{
"presets": [ "es2015", "stage-0" ]
}
package.json文件
"devDependencies": {
"babel-core": "^6.0.20",
"babel-preset-es2015": "^6.0.15",
"babel-preset-stage-0": "^6.0.15"
}
.js文件
"use strict";
async function foo() {
await bar();
}
function bar() { }
exports.default = foo;
在没有async/await的情况下正常使用它，效果很好。知道我做错了什么吗？
当前回答
我的工作babel 7样板，用于与再生器运行时反应：
巴氏合金
{
"presets": [
[
"@babel/preset-env",
{
"targets": {
"node": true,
},
},
],
"@babel/preset-react",
],
"plugins": [
"@babel/plugin-syntax-class-properties",
"@babel/plugin-proposal-class-properties"
]
}
包.json
...
"devDependencies": {
"@babel/core": "^7.0.0-0",
"@babel/plugin-proposal-class-properties": "^7.4.4",
"@babel/plugin-syntax-class-properties": "^7.2.0",
"@babel/polyfill": "^7.4.4",
"@babel/preset-env": "^7.4.5",
"@babel/preset-react": "^7.0.0",
"babel-eslint": "^10.0.1",
...
main.js
import "@babel/polyfill";
....
其他回答
根据以下示例更新.babelrc文件，它将起作用。
如果您使用的是@babel/preset-env包
{
"presets": [
[
"@babel/preset-env", {
"targets": {
"node": "current"
}
}
]
]
}
or if you are using babel-preset-env package
{
"presets": [
[
"env", {
"targets": {
"node": "current"
}
}
]
]
}
供将来参考：
从Babel版本7.0.0-beta.55起，已删除舞台预设
参考博客https://babeljs.io/blog/2018/07/27/removing-babels-stage-presets
异步等待仍然可以由
https://babeljs.io/docs/en/babel-plugin-transform-async-to-generator#usage
安装
npm install --save-dev @babel/plugin-transform-async-to-generator
babelrc中的用法
{
"presets": ["@babel/preset-env"],
"plugins": ["@babel/plugin-transform-async-to-generator"]
}
并使用babel polyfillhttps://babeljs.io/docs/en/babel-polyfill
安装
npm install --save @babel/polyfill
webpack.config.js
module.exports = {
entry: ["@babel/polyfill", "./app/js"],
};
安装babel polyfillnpm安装--保存@babel/polyfill更新webpack文件entry:[“@babel/polyfill”，“<your enter js file>”]
这些答案中的大多数都推荐了使用WebPack处理此错误的解决方案。但如果有人在使用RollUp（就像我一样），以下是最终对我有效的方法（只需一个提示，将这个polyfill广告捆绑在一起，总输出大小约为10k）：
巴氏合金
{
"presets": [
[
"env",
{
"modules": false,
"targets": {
"browsers": ["last 2 versions"]
}
}
]
],
"plugins": ["external-helpers",
[
"transform-runtime",
{
"polyfill": false,
"regenerator": true
}
]]
}
汇总配置.js
import resolve from 'rollup-plugin-node-resolve';
import babel from 'rollup-plugin-babel';
import uglify from 'rollup-plugin-uglify';
import commonjs from 'rollup-plugin-commonjs';
export default {
input: 'src/entry.js',
output: {
file: 'dist/bundle.js',
format: 'umd',
name: 'MyCoolLib',
exports: 'named'
},
sourcemap: true,
plugins: [
commonjs({
// polyfill async/await
'node_modules/babel-runtime/helpers/asyncToGenerator.js': ['default']
}),
resolve(),
babel({
runtimeHelpers: true,
exclude: 'node_modules/**', // only transpile our source code
}),
uglify()
]
};
当我尝试使用ES6生成器时，使用gulf with rollup时会出现以下错误：
gulp.task('scripts', () => {
return rollup({
entry: './app/scripts/main.js',
format: "iife",
sourceMap: true,
plugins: [babel({
exclude: 'node_modules/**',
"presets": [
[
"es2015-rollup"
]
],
"plugins": [
"external-helpers"
]
}),
includePaths({
include: {},
paths: ['./app/scripts'],
external: [],
extensions: ['.js']
})]
})
.pipe(source('app.js'))
.pipe(buffer())
.pipe(sourcemaps.init({
loadMaps: true
}))
.pipe(sourcemaps.write('.'))
.pipe(gulp.dest('.tmp/scripts'))
.pipe(reload({ stream: true }));
});
我可能认为解决方案是将babel polyfill作为bower组件：
bower install babel-polyfill --save
并将其作为依赖项添加到index.html中：
<script src="/bower_components/babel-polyfill/browser-polyfill.js"></script>
