Tsserver expects `@angular/language-service` to provide a factory function
as the default export (commonjs-style) of the package.
The current implementation side steps TypeScript's import syntax by using
`module.exports = factory`.
This allows the code to incorrectly re-export other symbols:
```ts
export * from './api';
```
which transpiles to:
```js
var tslib_1 = require("tslib");
tslib_1.__exportStar(require("@angular/language-service/api"), exports);
```
Doing this meant that the package now has a runtime dependency on `tslib`,
which is totally unnecessary.
With the proper `export =` syntax, `tslib` is removed, and no other exports
are allowed.
Output:
```js
(function (factory) {
if (typeof module === "object" && typeof module.exports === "object") {
var v = factory(require, exports);
if (v !== undefined) module.exports = v;
}
else if (typeof define === "function" && define.amd) {
define("@angular/language-service", ["require", "exports"], factory);
}
})(function (require, exports) {
"use strict";
return function factory(tsModule) {
var plugin;
return {
create: function (info) {
var config = info.config;
var bundleName = config.ivy ? 'ivy.js' : 'language-service.js';
plugin = require("./bundles/" + bundleName)(tsModule);
return plugin.create(info);
},
getExternalFiles: function (project) {
var _a, _b;
return (_b = (_a = plugin === null || plugin === void 0 ? void 0 : plugin.getExternalFiles) === null || _a === void 0 ? void 0 : _a.call(plugin, project)) !== null && _b !== void 0 ? _b : [];
},
onConfigurationChanged: function (config) {
var _a;
(_a = plugin === null || plugin === void 0 ? void 0 : plugin.onConfigurationChanged) === null || _a === void 0 ? void 0 : _a.call(plugin, config);
},
};
};
});
```
PR Close#41165