示例
const obj = {
foo: {
bar: {
baz: 42,
},
},
};
const baz = obj?.foo?.bar?.baz; // 42
const safe = obj?.qux?.baz; // undefined
// Optional chaining and normal chaining can be intermixed
obj?.foo.bar?.baz; // Only access `foo` if `obj` exists, and `baz` if
// `bar` exists
// Example usage with bracket notation:
obj?.['foo']?.bar?.baz // 42
npm install --save-dev @babel/plugin-proposal-optional-chaining
babel.config.js中添加plugins: ["@babel/plugin-proposal-optional-chaining"]
module.exports = {
presets: [
'@vue/app'
],
plugins: ["@babel/plugin-proposal-optional-chaining"]
}
目前只能在js中使用（编辑器报错不用管），template中还是会报错。
参考文章
https://babeljs.io/docs/en/next/babel-plugin-proposal-optional-chaining
