feat: remove top-level typescript import statements (#1259)

* feat: remove top-level typescript import statements

* Update package.json

* Update CHANGELOG.md

Co-authored-by: John Reilly <johnny_reilly@hotmail.com>

CHANGELOG.md

@@ -1,5 +1,8 @@
 # Changelog
 
+## v8.1.0
+* [feat: remove top-level typescript import statements](https://github.com/TypeStrong/ts-loader/pull/1259) - thanks @ulivz
+
 ## v8.0.18
 * [Perf: Optimize fileExists callback path](https://github.com/TypeStrong/ts-loader/issues/1266) - thanks @berickson1
 

package.json

@@ -1,6 +1,6 @@
 {
   "name": "ts-loader",
-  "version": "8.0.18",
+  "version": "8.1.0",
   "description": "TypeScript loader for webpack",
   "main": "index.js",
   "types": "dist",

src/after-compile.ts

@@ -1,5 +1,5 @@
 import * as path from 'path';
-import * as ts from 'typescript';
+import type * as ts from 'typescript';
 import * as webpack from 'webpack';
 
 import * as constants from './constants';

src/compilerSetup.ts

@@ -1,5 +1,5 @@
 import * as semver from 'semver';
-import * as typescript from 'typescript';
+import type * as typescript from 'typescript';
 
 import { LoaderOptions } from './interfaces';
 import * as logger from './logger';
@@ -52,7 +52,8 @@ export function getCompiler(loaderOptions: LoaderOptions, log: logger.Logger) {
 }
 
 export function getCompilerOptions(
-  configParseResult: typescript.ParsedCommandLine
+  configParseResult: typescript.ParsedCommandLine,
+  compiler: typeof typescript
 ) {
   const compilerOptions = Object.assign({}, configParseResult.options, {
     skipLibCheck: true,
@@ -63,9 +64,9 @@ export function getCompilerOptions(
   if (
     compilerOptions.module === undefined &&
     compilerOptions.target !== undefined &&
-    compilerOptions.target < typescript.ScriptTarget.ES2015
+    compilerOptions.target < compiler.ScriptTarget.ES2015
   ) {
-    compilerOptions.module = typescript.ModuleKind.CommonJS;
+    compilerOptions.module = compiler.ModuleKind.CommonJS;
   }
 
   if (configParseResult.options.configFile) {

src/config.ts

@@ -1,6 +1,6 @@
 import { Chalk } from 'chalk';
 import * as path from 'path';
-import * as typescript from 'typescript';
+import type * as typescript from 'typescript';
 import * as webpack from 'webpack';
 
 import { getCompilerOptions } from './compilerSetup';
@@ -187,7 +187,7 @@ export function getParsedCommandLine(
     extendedConfigCache
   );
   if (result) {
-    result.options = getCompilerOptions(result);
+    result.options = getCompilerOptions(result, compiler);
   }
   return result;
 }

src/index.ts

@@ -1,7 +1,7 @@
 import * as crypto from 'crypto';
 import * as loaderUtils from 'loader-utils';
 import * as path from 'path';
-import * as typescript from 'typescript';
+import type * as typescript from 'typescript';
 import * as webpack from 'webpack';
 
 import * as constants from './constants';

src/instances.ts

@@ -1,7 +1,7 @@
 import * as chalk from 'chalk';
 import * as fs from 'fs';
 import * as path from 'path';
-import * as typescript from 'typescript';
+import type * as typescript from 'typescript';
 import * as webpack from 'webpack';
 
 import { makeAfterCompile } from './after-compile';
@@ -202,7 +202,7 @@ function successfulTypeScriptInstance(
     };
   }
 
-  const compilerOptions = getCompilerOptions(configParseResult);
+  const compilerOptions = getCompilerOptions(configParseResult, compiler);
   const rootFileNames = new Set<string>();
   const files: TSFiles = new Map();
   const otherFiles: TSFiles = new Map();

src/interfaces.ts

@@ -1,4 +1,4 @@
-import * as typescript from 'typescript';
+import type * as typescript from 'typescript';
 
 import { Chalk } from 'chalk';
 import * as logger from './logger';

src/servicesHost.ts

@@ -1,5 +1,5 @@
 import * as path from 'path';
-import * as typescript from 'typescript';
+import type * as typescript from 'typescript';
 import * as webpack from 'webpack';
 import { getParsedCommandLine } from './config';
 import * as constants from './constants';

src/utils.ts

@@ -2,7 +2,7 @@ import { Chalk } from 'chalk';
 import * as fs from 'fs';
 import * as micromatch from 'micromatch';
 import * as path from 'path';
-import * as typescript from 'typescript';
+import type * as typescript from 'typescript';
 
 import constants = require('./constants');
 import {