@cognibox/babel-plugin-es5-proxy
v3.2.2
Published
Babel plugin to use ES6 Proxy in ES5. Inspired by the work of https://github.com/krzkaczor/babel-plugin-proxy, fixed for babel7 (and a lot more).
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babel-plugin-es5-proxy
Babel plugin to use ES6 Proxy in ES5. Inspired by the work of https://github.com/krzkaczor/babel-plugin-proxy, fixed for babel7 (and a lot more).
Installation
npm install --save-dev git+https://github.com/cognibox/babel-plugin-es5-proxy.git
Usage
plugins: ['babel-plugin-es5-proxy'],
Options
plugins: [['babel-plugin-es5-proxy', { useBuiltIns: '...', modules: false, targets: { ... } }]],
modules
Type: boolean
Values: "amd" | "umd" | "systemjs" | "commonjs" | "cjs" | "auto" | false
Default: false
targets
Type: object
Default: { ie: 9, uglify: true }
useBuiltIns
Type: string
Values: "usage" | "entry" | false
Default: false
The plugin has 100% behaviour coverage.
How it works
Everytime a property is accessed or set on an object, it is replaced by a function call to respectively globalGetter
or globalSetter
which either accesses or set the original property or calls the getter or setter in the Proxy.
Example
The following code
let obj = {};
obj.foo = 5;
obj.foo;
becomes
let obj = {};
globalSetter(obj, 'foo', 5);
globalGetter(obj, 'foo');
The plugin supports any expression in the getter and the setter,
let obj = {};
let bar = 'fo';
obj[bar + 'o'] = 5;
obj.foo;
becomes
let obj = {};
let bar = 'fo';
globalSetter(obj, bar + 'o', 5);
globalGetter(obj, 'foo');
When a proxy with a getter is defined, the call goes through the getter
let obj = new Proxy({}, { get(property) { return 4 } })
obj.foo // 4
The interface is identical to es6 Proxies.