babel-plugin-safe-member-expression

safe member expression

only auto enabled in BlockStatement

feature:

• Safer MemberExpression
• Safer CallExpression with MemberExpression
• Safer AssignmentExpression with MemberExpression

参数

match

默认值：/\/src.*\.jsx?/i

描述：只有被 match 中的文件路径才会进入插件转换

exclude

默认值：/\/node_modules.*\.jsx?/i

描述：被 exclude 匹配的路径不会进入插件转换

Example

Safer MemberExpression

In

const foo = hello['world'];
let hello = this.state['foo'].bar;

Out

var _object, _object2, _object3;

const foo = hello == null ? null : hello['world'];
let hello = (_object = (_object2 = (_object3 = this) == null ? null : _object3.state) == null ? null : _object2['foo']) == null ? null : _object.bar;

Safer CallExpression with MemberExpression

In

const data = this.foo.bar.ok();

Out

var _object, _object2, _object3;

const data = (_object = (_object2 = (_object3 = this) == null ? null : _object3.foo) == null ? null : _object2.bar) == null ? null : _object.ok ? _object.ok() : null;

Safer AssignmentExpression with MemberExpression

In

foo['bar'] = x.y;
x.y.z = 'xxx';

Out

var _object;

(foo || (foo = {}))['bar'] = x == null ? null : x.y;
((_object = x || (x = {})).y || (_object.y = {})).z = 'xxx';

Installation

$ npm install babel-plugin-safe-member-expression

Usage

Via .babelrc (Recommended)

.babelrc

{
  "plugins": ["safe-member-expression"]
}

Via CLI

$ babel --plugins safe-member-expression script.js

Via Node API

require("babel-core").transform("code", {
  plugins: ["safe-member-expression"]
});