Support project references

.travis.yml

@@ -9,6 +9,7 @@ sudo: required
 install:
   - yarn install
   - yarn build
+  - yarn lint
   - yarn add $TYPESCRIPT
 env:
   - TYPESCRIPT=typescript@3.0.1

CHANGELOG.md

@@ -1,6 +1,11 @@
 # Changelog
 
+## 5.2.0
+
+* [feat: Initial support for project references - `projectReferences`](https://github.com/TypeStrong/ts-loader/pull/817) - thanks @andrewbranch!
+
 ## 5.1.1
+
 * [fix(getTranspilationEmit): pass the raw path to transpileModule](https://github.com/TypeStrong/ts-loader/pull/835) - thanks @Brooooooklyn 
 
 ## 5.1.0

README.md

@@ -543,7 +543,7 @@ Extending `tsconfig.json`:
 
 Note that changes in the extending file while not be respected by `ts-loader`. Its purpose is to satisfy the code editor.
 
-### experimentalFileCaching _(boolean) (default=false)_
+#### experimentalFileCaching _(boolean) (default=false)_
 
 By default whenever the TypeScript compiler needs to check that a file/directory exists or resolve symlinks it makes syscalls.
 It does not cache the result of these operations and this may result in many syscalls with the same arguments ([see comment](https://github.com/TypeStrong/ts-loader/issues/825#issue-354725524) with example).
@@ -552,6 +552,32 @@ In some cases it may produce performance degradation.
 This flag enables caching for some FS-functions like `fileExists`, `realpath` and `directoryExists` for TypeScript compiler.
 Note that caches are cleared between compilations.
 
+#### projectReferences _(boolean) (default=false)_
+
+**TL;DR:** Using project references currently requires building referenced projects outside of ts-loader. We don’t want to keep it that way, but we’re releasing what we’ve got now. To try it out, you’ll need to pass `projectReferences: true` to `loaderOptions`.
+
+ts-loader has partial support for [project references](https://www.typescriptlang.org/docs/handbook/project-references.html) in that it will _load_ dependent composite projects that are already built, but will not currently _build/rebuild_ those upstream projects. The best way to explain exactly what this means is through an example. Say you have a project with a project reference pointing to the `lib/` directory:
+
+```
+tsconfig.json
+app.ts
+lib/
+  tsconfig.json
+  niftyUtil.ts
+```
+
+And we’ll assume that the root `tsconfig.json` has `{ "references": { "path": "lib" } }`, which means that any import of a file that’s part of the `lib` sub-project is treated as a reference to another project, not just a reference to a TypeScript file. Before discussing how ts-loader handles this, it’s helpful to review at a really basic level what `tsc` itself does here. If you were to run `tsc` on this tiny example project, the build would fail with the error:
+
+```
+error TS6305: Output file 'lib/niftyUtil.d.ts' has not been built from source file 'lib/niftyUtil.ts'.
+```
+
+Using project references actually instructs `tsc` _not_ to build anything that’s part of another project from source, but rather to look for any `.d.ts` and `.js` files that have already been generated from a previous build. Since we’ve never built the project in `lib` before, those files don’t exist, so building the root project fails. Still just thinking about how `tsc` works, there are two options to make the build succeed: either run `tsc -p lib/tsconfig.json` _first_, or simply run `tsc --build`, which will figure out that `lib` hasn’t been built and build it first for you.
+
+Ok, so how is that relevant to ts-loader? Because the best way to think about what ts-loader does with project references is that it acts like `tsc`, but _not_ like `tsc --build`. If you run ts-loader on a project that’s using project references, and any upstream project hasn’t been built, you’ll get the exact same `error TS6305` that you would get with `tsc`. If you modify a source file in an upstream project and don’t rebuild that project, `ts-loader` won’t have any idea that you’ve changed anything—it will still be looking at the output from the last time you _built_ that file.
+
+**“Hey, don’t you think that sounds kind of useless and terrible?”** Well, sort of. You can consider it a work-in-progress. It’s true that on its own, as of today, ts-loader doesn’t have everything you need to take advantage of project references in Webpack. In practice, though, _consuming_ upstream projects and _building_ upstream projects are somewhat separate concerns. Building them will likely come in a future release. For background, see the [original issue](https://github.com/TypeStrong/ts-loader/issues/815).
+
 ### Usage with Webpack watch
 
 Because TS will generate .js and .d.ts files, you should ignore these files, otherwise watchers may go into an infinite watch loop. For example, when using Webpack, you may wish to add this to your webpack.conf.js file:

appveyor.yml

@@ -15,6 +15,7 @@ install:
   - ps: Install-Product node $env:nodejs_version
   - yarn install
   - yarn build
+  - yarn lint
   - yarn add %TYPESCRIPT%
 test_script:
   - node --version

package.json

@@ -1,11 +1,12 @@
 {
   "name": "ts-loader",
-  "version": "5.1.1",
+  "version": "5.2.0",
   "description": "TypeScript loader for webpack",
   "main": "index.js",
   "types": "dist/types/index.d.ts",
   "scripts": {
     "build": "tsc --version && tsc --project \"./src\"",
+    "lint": "tslint --project \"./src\"",
     "comparison-tests": "tsc --project \"./test/comparison-tests\" && npm link ./test/comparison-tests/testLib && node test/comparison-tests/run-tests.js",
     "comparison-tests-generate": "node test/comparison-tests/stub-new-version.js",
     "execution-tests": "npm i -g pnpm && node test/execution-tests/run-tests.js",
@@ -78,6 +79,8 @@
     "mocha": "^5.0.0",
     "prettier": "^1.11.1",
     "rimraf": "^2.6.2",
+    "tslint": "^5.11.0",
+    "tslint-config-prettier": "^1.15.0",
     "typescript": "^3.0.1",
     "webpack": "^4.5.0",
     "webpack-cli": "^2.1.2"

src/after-compile.ts

@@ -1,15 +1,20 @@
 import * as path from 'path';
-import { collectAllDependants, formatErrors } from './utils';
+
 import * as constants from './constants';
+import { getEmitOutput } from './instances';
 import {
+  TSFile,
   TSFiles,
   TSInstance,
   WebpackCompilation,
   WebpackError,
-  WebpackModule,
-  TSFile
+  WebpackModule
 } from './interfaces';
-import { getEmitOutput } from './instances';
+import {
+  collectAllDependants,
+  formatErrors,
+  isUsingProjectReferences
+} from './utils';
 
 export function makeAfterCompile(
   instance: TSInstance,
@@ -60,6 +65,7 @@ export function makeAfterCompile(
 
     instance.filesWithErrors = filesWithErrors;
     instance.modifiedFiles = null;
+    instance.projectsMissingSourceMaps = new Set();
 
     callback();
   };
@@ -171,7 +177,7 @@ function provideErrorsToWebpack(
     otherFiles
   } = instance;
 
-  let filePathRegex = !!compilerOptions.checkJs
+  const filePathRegex = !!compilerOptions.checkJs
     ? constants.dtsTsTsxJsJsxRegex
     : constants.dtsTsTsxRegex;
 
@@ -181,6 +187,15 @@ function provideErrorsToWebpack(
     }
 
     const sourceFile = program && program.getSourceFile(filePath);
+
+    // If the source file is undefined, that probably means it’s actually part of an unbuilt project reference,
+    // which will have already produced a more useful error than the one we would get by proceeding here.
+    // If it’s undefined and we’re not using project references at all, I guess carry on so the user will
+    // get a useful error about which file was unexpectedly missing.
+    if (isUsingProjectReferences(instance) && !sourceFile) {
+      continue;
+    }
+
     const errors = program
       ? [
           ...program.getSyntacticDiagnostics(sourceFile),

src/compilerSetup.ts

@@ -1,9 +1,9 @@
-import * as typescript from 'typescript';
 import * as semver from 'semver';
+import * as typescript from 'typescript';
 
 import * as constants from './constants';
-import * as logger from './logger';
 import { LoaderOptions } from './interfaces';
+import * as logger from './logger';
 
 export function getCompiler(loaderOptions: LoaderOptions, log: logger.Logger) {
   let compiler: typeof typescript | undefined;

src/config.ts

@@ -1,9 +1,9 @@
-import * as typescript from 'typescript';
-import * as path from 'path';
 import { Chalk } from 'chalk';
+import * as path from 'path';
+import * as typescript from 'typescript';
+import { LoaderOptions, Webpack, WebpackError } from './interfaces';
 import * as logger from './logger';
 import { formatErrors } from './utils';
-import { LoaderOptions, Webpack, WebpackError } from './interfaces';
 
 interface ConfigFile {
   config?: any;

src/constants.ts

@@ -11,11 +11,14 @@ export const ScriptTargetES2015 = 2;
 
 export const ModuleKindCommonJs = 1;
 
+export const extensionRegex = /\.[^.]+$/;
+export const tsxRegex = /\.tsx$/i;
 export const tsTsxRegex = /\.ts(x?)$/i;
 export const dtsDtsxOrDtsDtsxMapRegex = /\.d\.ts(x?)(\.map)?$/i;
 export const dtsTsTsxRegex = /(\.d)?\.ts(x?)$/i;
 export const dtsTsTsxJsJsxRegex = /((\.d)?\.ts(x?)|js(x?))$/i;
 export const tsTsxJsJsxRegex = /\.tsx?$|\.jsx?$/i;
 export const jsJsx = /\.js(x?)$/i;
 export const jsJsxMap = /\.js(x?)\.map$/i;
+export const jsonRegex = /\.json$/i;
 export const nodeModules = /node_modules/i;