info
This plugin is included in @babel/preset-env, in ES2022
A class with a static block will be transformed into a static private property, whose initializer is the static block wrapped in an IIAFE (immediate invoked arrow function expression).
Example
JavaScript
class C {
static #x = 42;
static y;
static {
try {
this.y = doSomethingWith(this.#x);
} catch {
this.y = "unknown";
}
}
}
will be transformed to
JavaScript
class C {
static #x = 42;
static y;
static #_ = (() => {
try {
this.y = doSomethingWith(this.#x);
} catch {
this.y = "unknown";
}
})();
}
Because the output code includes private class properties, if you are already using other class feature plugins (e.g. @babel/plugin-transform-class-properties), be sure to place it before the others.
babel.config.json
{
"plugins": [
"@babel/plugin-transform-class-static-block",
"@babel/plugin-transform-class-properties"
]
}
Installation
- npm
- Yarn
- pnpm
- Bun
npm install --save-dev @babel/plugin-transform-class-static-block
Usage
With a configuration file (Recommended)
babel.config.json
{
"plugins": ["@babel/plugin-transform-class-static-block"]
}
Via CLI
Shell
babel --plugins @babel/plugin-transform-class-static-block script.js
Via Node API
JavaScript
require("@babel/core").transformSync("code", {
plugins: ["@babel/plugin-transform-class-static-block"],
});