341bdab90c
* Update decorators parsing
This commit introduces three changes:
1) Class properties can be decorated
2) Decorators can contain arbitrary expressions, using @(...)
3) The Decorator node type has a new property, "arguments". This
makes it possible do distinguish @dec() and @(dec()), which have
different behaviors because @(dec()) is equivalent to @(dec())().
* Rename Decorator#expression to Decorator#callee
* Add test for @dec()()
@babel/plugin-proposal-decorators
Compile class and object decorators to ES5
Example
(examples are from proposal)
Simple class decorator
@annotation
class MyClass { }
function annotation(target) {
target.annotated = true;
}
Class decorator
@isTestable(true)
class MyClass { }
function isTestable(value) {
return function decorator(target) {
target.isTestable = value;
}
}
Class function decorator
class C {
@enumerable(false)
method() { }
}
function enumerable(value) {
return function (target, key, descriptor) {
descriptor.enumerable = value;
return descriptor;
}
}
Installation
npm install --save-dev @babel/plugin-proposal-decorators
Usage
Add the following line to your .babelrc file:
{
"plugins": ["@babel/plugin-proposal-decorators"]
}
NOTE: Order of Plugins Matters!
If you are including your plugins manually and using @babel/plugin-proposal-class-properties, make sure that @babel/plugin-proposal-decorators comes before @babel/plugin-proposal-class-properties.
Currently, @babel/plugin-proposal-class-properties must be used in loose mode to support the @babel/plugin-proposal-decorators. To use @babel/plugin-proposal-class-properties in spec mode with decorators, wait for the next major version of decorators (Stage 2).
Wrong:
{
"plugins": [
"@babel/plugin-proposal-class-properties",
"@babel/plugin-proposal-decorators"
]
}
Right:
{
"plugins": [
"@babel/plugin-proposal-decorators",
["@babel/plugin-proposal-class-properties", { "loose" : true }]
]
}
Via CLI
babel --plugins @babel/plugin-proposal-decorators script.js
Via Node API
require("@babel/core").transform("code", {
plugins: ["@babel/plugin-proposal-decorators"]
});