index.js
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"use strict";
Object.defineProperty(exports, "__esModule", {
value: true
});
exports.default = void 0;
var _helperPluginUtils = require("@babel/helper-plugin-utils");
var _core = require("@babel/core");
var _default = (0, _helperPluginUtils.declare)(api => {
api.assertVersion(7);
return {
name: "transform-new-target",
visitor: {
MetaProperty(path) {
const meta = path.get("meta");
const property = path.get("property");
const {
scope
} = path;
if (meta.isIdentifier({
name: "new"
}) && property.isIdentifier({
name: "target"
})) {
const func = path.findParent(path => {
if (path.isClass()) return true;
if (path.isFunction() && !path.isArrowFunctionExpression()) {
if (path.isClassMethod({
kind: "constructor"
})) {
return false;
}
return true;
}
return false;
});
if (!func) {
throw path.buildCodeFrameError("new.target must be under a (non-arrow) function or a class.");
}
const {
node
} = func;
if (_core.types.isMethod(node)) {
path.replaceWith(scope.buildUndefinedNode());
return;
}
const constructor = _core.types.memberExpression(_core.types.thisExpression(), _core.types.identifier("constructor"));
if (func.isClass()) {
path.replaceWith(constructor);
return;
}
if (!node.id) {
node.id = scope.generateUidIdentifier("target");
} else {
let scope = path.scope;
const name = node.id.name;
while (scope !== func.parentPath.scope) {
if (scope.hasOwnBinding(name) && !scope.bindingIdentifierEquals(name, node.id)) {
scope.rename(name);
}
scope = scope.parent;
}
}
path.replaceWith(_core.types.conditionalExpression(_core.types.binaryExpression("instanceof", _core.types.thisExpression(), _core.types.cloneNode(node.id)), constructor, scope.buildUndefinedNode()));
}
}
}
};
});
exports.default = _default;