babel-polyfill
(已弃用从 Babel 7.4 开始)是必需的。您还必须安装它才能使 async/await 工作。
npm i -D babel-core babel-polyfill babel-preset-es2015 babel-preset-stage-0 babel-loader
包.json
"devDependencies": {
"babel-core": "^6.0.20",
"babel-polyfill": "^6.0.16",
"babel-preset-es2015": "^6.0.15",
"babel-preset-stage-0": "^6.0.15"
}
.babelrc
{
"presets": [ "es2015", "stage-0" ]
}
带有 async/await 的 .js(示例代码)
"use strict";
export default async function foo() {
var s = await bar();
console.log(s);
}
function bar() {
return "bar";
}
在启动文件中
require("babel-core/register");
require("babel-polyfill");
如果您正在使用webpack你需要把它作为你的第一个值entry
webpack 配置文件中的数组(通常webpack.config.js
),根据 @Cemen 评论:
module.exports = {
entry: ['babel-polyfill', './test.js'],
output: {
filename: 'bundle.js'
},
module: {
loaders: [
{ test: /\.jsx?$/, loader: 'babel', }
]
}
};
如果你想用 babel 运行测试,那么使用:
mocha --compilers js:babel-core/register --require babel-polyfill