packages/babel-plugin-transform-instanceof/src/index.js
import { declare } from "@babel/helper-plugin-utils";
import { types as t } from "@babel/core";
export default declare(api => {
api.assertVersion(7);
return {
name: "transform-instanceof",
visitor: {
BinaryExpression(path) {
const { node } = path;
if (node.operator === "instanceof") {
const helper = this.addHelper("instanceof");
const isUnderHelper = path.findParent(path => {
return (
(path.isVariableDeclarator() && path.node.id === helper) ||
(path.isFunctionDeclaration() &&
path.node.id &&
path.node.id.name === helper.name)
);
});
if (isUnderHelper) {
return;
} else {
path.replaceWith(t.callExpression(helper, [node.left, node.right]));
}
}
},
},
};
});