docs(config): adds doc for some config options

Adds doc for options: `compiler`, `tsConfig`, `isolatedModules`

Author: huafu

docs/user/config.md

@@ -11,22 +11,22 @@ In most of the case, simply adding `preset: 'ts-jest'` to your Jest config shoul
 
 <div class="row"><div class="col-md-6" markdown="block">
 ```js
-// package.json
+// jest.config.js
+module.exports = {
+  // [...]
+  preset: 'ts-jest'
+};
+```
+</div><div class="col-md-6" markdown="block">
+```js
+// OR package.json
 {
   // [...]
   "jest": {
     "preset": "ts-jest"
   }
 }
 ```
-</div><div class="col-md-6" markdown="block">
-```js
-// jest.config.js
-module.exports = {
-  // [...]
-  preset: 'ts-jest'
-};
-```
 </div></div>
 
 ### Advanced
@@ -53,7 +53,19 @@ All configration of TSJest specific options are located under `globals.ts-jest`
 
 <div class="row"><div class="col-md-6" markdown="block">
 ```js
-// package.json
+// jest.config.js
+module.exports = {
+  // [...]
+  globals: {
+    'ts-jest': {
+      // TSJest configuration goes here
+    }
+  }
+};
+```
+</div><div class="col-md-6" markdown="block">
+```js
+// OR package.json
 {
   // [...]
   "jest": {
@@ -65,27 +77,15 @@ All configration of TSJest specific options are located under `globals.ts-jest`
   }
 }
 ```
-</div><div class="col-md-6" markdown="block">
-```js
-// jest.config.js
-module.exports = {
-  // [...]
-  globals: {
-    'ts-jest': {
-      // TSJest configuration goes here
-    }
-  }
-};
-```
 </div></div>
 
 ### Options
 
 All options have default values which should fit most of the projects.
 
-- **`compiler`**: TypeScript module to use as compiler.
-- **`tsConfig`**: TypeScript compiler related configuration.
-- **`isolatedModules`**: Enables/disables the TypeScript language service.
-- **`diagnostics`**: Diagnostics related configuration.
-- **`babelConfig`**: Babel(Jest) related configuration.
-- **`stringifyContentPathRegex`**: Configure which file(s) will become a module returning its content.
+- [**`compiler`**: TypeScript module to use as compiler](config/compiler).
+- [**`tsConfig`**: TypeScript compiler related configuration.](config/tsConfig)
+- [**`isolatedModules`**: Enables/disables the TypeScript language service.](config/isolatedModules)
+- [**`diagnostics`**: Diagnostics related configuration.](config/diagnostics)
+- [**`babelConfig`**: Babel(Jest) related configuration.](config/babelConfig)
+- [**`stringifyContentPathRegex`**: Configure which file(s) will become a module returning its content.](config/stringifyContentPathRegex)

docs/user/config/compiler.md

@@ -0,0 +1,39 @@
+---
+title: Compiler option
+---
+
+The `compiler` option allows you to define the compiler to be used. It'll be used to load the NodeJS module holding the TypeScript compiler.
+
+The default value is `typescript`, which will load the original [TypeScript compiler module](https://www.npmjs.com/package/typescript). The version loaded will depend on the one installed in your project.
+
+If you use a custom compiler, such as `ttypescript` for example, be sure its API is the same as the original TypeScript, at least for what TSJest is using.
+
+### Example:
+
+<div class="row"><div class="col-md-6" markdown="block">
+```js
+// jest.config.js
+module.exports = {
+  // [...]
+  globals: {
+    'ts-jest': {
+      compiler: 'ttypsecript'
+    }
+  }
+};
+```
+</div><div class="col-md-6" markdown="block">
+```js
+// OR package.json
+{
+  // [...]
+  "jest": {
+    "globals": {
+      "ts-jest": {
+        "compiler": "ttypsecript"
+      }
+    }
+  }
+}
+```
+</div></div>

docs/user/config/isolatedModules.md

@@ -0,0 +1,39 @@
+---
+title: Isolated Modules option
+---
+
+By default TSJest uses TypeScript compiler in the context of a project (yours), with full type-checking and features. But it can also be used to compile each file separatly, as an isolated module. That's what the `isolatedModules` option (which defaults to `false`) comes for.
+
+You'll loose type-checking ability and some features such as `const enum`, but in the case you plan on using Jest with the cache disabled (`jest --no-cache`), your tests will then run much faster.
+
+Here is how to disable type-checking and compile each file as an isolated module:
+
+### Example:
+
+<div class="row"><div class="col-md-6" markdown="block">
+```js
+// jest.config.js
+module.exports = {
+  // [...]
+  globals: {
+    'ts-jest': {
+      isolatedModules: true
+    }
+  }
+};
+```
+</div><div class="col-md-6" markdown="block">
+```js
+// OR package.json
+{
+  // [...]
+  "jest": {
+    "globals": {
+      "ts-jest": {
+        "isolatedModules": false
+      }
+    }
+  }
+}
+```
+</div></div>

docs/user/config/tsConfig.md

@@ -0,0 +1,111 @@
+---
+title: TypeScript Config option
+---
+
+The `tsConfig` option allows you to define the which `tsconfig` JSON file to use. An inline compiler options object can also be specified instead of the path to a file.
+
+By default, TSJest will do like `tsc` and use the project's `tsconfig.json` file. If it cannot find one, it'l use defaults TypeScript compiler options (except `es5` is used as target instead of `es3`).
+
+If you need to use defaults and force TSJest to use the defaults even if there is a `tsconfig.json`, you can set this option to `false`.
+
+#### Examples
+
+### Path to a `tsconfig` file:
+
+The path should be relative to the current working directory where you start Jest from. You can also use `<rootDir>` in the path, or use an absolute path (this last one is strongly not recommanded).
+
+<div class="row"><div class="col-md-6" markdown="block">
+```js
+// jest.config.js
+module.exports = {
+  // [...]
+  globals: {
+    'ts-jest': {
+      tsConfig: 'tsconfig.test.json'
+    }
+  }
+};
+```
+</div><div class="col-md-6" markdown="block">
+```js
+// OR package.json
+{
+  // [...]
+  "jest": {
+    "globals": {
+      "ts-jest": {
+        "tsConfig": "tsconfig.test.json"
+      }
+    }
+  }
+}
+```
+</div></div>
+
+### Inline compiler options:
+
+Refer to the [TypeScript compiler options](https://www.typescriptlang.org/docs/handbook/compiler-options.html) to know what can be used. It's basically the same that you'd put in your `tsconfig.json`'s `compilerOptions`.
+
+<div class="row"><div class="col-md-6" markdown="block">
+```js
+// jest.config.js
+module.exports = {
+  // [...]
+  globals: {
+    'ts-jest': {
+      tsConfig: {
+        importHelpers: true
+      }
+    }
+  }
+};
+```
+</div><div class="col-md-6" markdown="block">
+```js
+// OR package.json
+{
+  // [...]
+  "jest": {
+    "globals": {
+      "ts-jest": {
+        "tsConfig": {
+          "importHelpers": true
+        }
+      }
+    }
+  }
+}
+```
+</div></div>
+
+### Disable auto-lookup:
+
+By default TSJest will try to find the `tsconfig.json` in your project. But you may want to not use it at all and keep TypeScript default options. You can achieve this by setting `tsConfig` to `false`.
+
+<div class="row"><div class="col-md-6" markdown="block">
+```js
+// jest.config.js
+module.exports = {
+  // [...]
+  globals: {
+    'ts-jest': {
+      tsConfig: false
+    }
+  }
+};
+```
+</div><div class="col-md-6" markdown="block">
+```js
+// OR package.json
+{
+  // [...]
+  "jest": {
+    "globals": {
+      "ts-jest": {
+        "tsConfig": false
+      }
+    }
+  }
+}
+```
+</div></div>