packages/babel-plugin-transform-classes/src/index.js
// @flow
import { declare } from "@babel/helper-plugin-utils";
import annotateAsPure from "@babel/helper-annotate-as-pure";
import nameFunction from "@babel/helper-function-name";
import splitExportDeclaration from "@babel/helper-split-export-declaration";
import { types as t } from "@babel/core";
import type { NodePath } from "@babel/traverse";
import globals from "globals";
import transformClass from "./transformClass";
const getBuiltinClasses = category =>
Object.keys(globals[category]).filter(name => /^[A-Z]/.test(name));
const builtinClasses = new Set([
...getBuiltinClasses("builtin"),
...getBuiltinClasses("browser"),
]);
export default declare((api, options) => {
api.assertVersion(7);
const { loose } = options;
// todo: investigate traversal requeueing
const VISITED = Symbol();
return {
name: "transform-classes",
visitor: {
ExportDefaultDeclaration(path: NodePath) {
if (!path.get("declaration").isClassDeclaration()) return;
splitExportDeclaration(path);
},
ClassDeclaration(path: NodePath) {
const { node } = path;
const ref = node.id || path.scope.generateUidIdentifier("class");
path.replaceWith(
t.variableDeclaration("let", [
t.variableDeclarator(ref, t.toExpression(node)),
]),
);
},
ClassExpression(path: NodePath, state: any) {
const { node } = path;
if (node[VISITED]) return;
const inferred = nameFunction(path);
if (inferred && inferred !== node) {
path.replaceWith(inferred);
return;
}
node[VISITED] = true;
path.replaceWith(
transformClass(path, state.file, builtinClasses, loose),
);
if (path.isCallExpression()) {
annotateAsPure(path);
if (path.get("callee").isArrowFunctionExpression()) {
path.get("callee").arrowFunctionToExpression();
}
}
},
},
};
});