fix: use single entry point for @angular/language-service

Starting from `@angular/language-service` v12.0.0-next.3, the package
will dynamically load View Engine or Ivy LS based on the config passed
to the plugin.

This reverts #1111

Author: kyliau

server/src/server.ts

@@ -10,7 +10,7 @@ import {generateHelpMessage, parseCommandLine} from './cmdline_utils';
 import {createLogger} from './logger';
 import {ServerHost} from './server_host';
 import {Session} from './session';
-import {NGLANGSVC, resolveNgLangSvc, resolveTsServer} from './version_provider';
+import {resolveNgLangSvc, resolveTsServer} from './version_provider';
 
 // Parse command line arguments
 const options = parseCommandLine(process.argv);
@@ -30,13 +30,14 @@ const ts = resolveTsServer(options.tsProbeLocations);
 const ng = resolveNgLangSvc(options.ngProbeLocations, options.ivy);
 
 // ServerHost provides native OS functionality
-const host = new ServerHost(options.ivy);
+const host = new ServerHost();
 
 // Establish a new server session that encapsulates lsp connection.
 const session = new Session({
   host,
   logger,
-  ngPlugin: NGLANGSVC,  // TypeScript allows only package names as plugin names.
+  // TypeScript allows only package names as plugin names.
+  ngPlugin: '@angular/language-service',
   resolvedNgLsPath: ng.resolvedPath,
   ivy: options.ivy,
   logToConsole: options.logToConsole,

server/src/server_host.ts

@@ -7,7 +7,6 @@
  */
 
 import * as ts from 'typescript/lib/tsserverlibrary';
-import {NGLANGSVC} from './version_provider';
 
 /**
  * `ServerHost` is a wrapper around `ts.sys` for the Node system. In Node, all
@@ -20,7 +19,7 @@ export class ServerHost implements ts.server.ServerHost {
   readonly newLine: string;
   readonly useCaseSensitiveFileNames: boolean;
 
-  constructor(private ivy: boolean) {
+  constructor() {
     this.args = ts.sys.args;
     this.newLine = ts.sys.newLine;
     this.useCaseSensitiveFileNames = ts.sys.useCaseSensitiveFileNames;
@@ -172,13 +171,9 @@ export class ServerHost implements ts.server.ServerHost {
 
   require(initialPath: string, moduleName: string) {
     try {
-      let modulePath = require.resolve(moduleName, {
+      const modulePath = require.resolve(moduleName, {
         paths: [initialPath],
       });
-      // TypeScript allows only package names as plugin names.
-      if (this.ivy && moduleName === NGLANGSVC) {
-        modulePath = this.resolvePath(modulePath + '/../ivy.js');
-      }
       return {
         module: require(modulePath),
         error: undefined,

server/src/session.ts

@@ -114,6 +114,7 @@ export class Session {
       pluginName: options.ngPlugin,
       configuration: {
         angularOnly: true,
+        ivy: options.ivy,
       },
     });
 

server/src/version_provider.ts

@@ -11,7 +11,6 @@ import * as path from 'path';
 
 const MIN_TS_VERSION = '4.1';
 const MIN_NG_VERSION = '12.0';
-export const NGLANGSVC = '@angular/language-service';
 const TSSERVERLIB = 'typescript/lib/tsserverlibrary';
 
 /**
@@ -120,8 +119,8 @@ function resolveTsServerFromTsdk(tsdk: string): NodeModule|undefined {
  * @param ivy true if Ivy language service is requested
  */
 export function resolveNgLangSvc(probeLocations: string[], ivy: boolean): NodeModule {
-  const packageName = ivy ? `${NGLANGSVC}/bundles/ivy` : NGLANGSVC;
-  return resolveWithMinVersion(packageName, MIN_NG_VERSION, probeLocations, NGLANGSVC);
+  const ngls = '@angular/language-service';
+  return resolveWithMinVersion(ngls, MIN_NG_VERSION, probeLocations, ngls);
 }
 
 /**