feat(config): add incremental option (#1418)

Author: ahnpnl

.eslintrc.js

@@ -7,6 +7,9 @@ module.exports = {
     ecmaVersion: 2020,
     sourceType: 'module',
     impliedStrict: true,
+    ecmaFeatures: {
+      jsx: true,
+    },
   },
   rules: {
     'no-console': ['error', { allow: ['warn', 'error', 'log'] }],

CHANGELOG.md

@@ -1,5 +1,5 @@
 <a name="25.2.1"></a>
-# [25.2.1](https://github.com/kulshekhar/ts-jest/compare/25.2.1...25.2.0) (2020-02-21)
+# [25.2.1](https://github.com/kulshekhar/ts-jest/compare/25.2.0...25.2.1) (2020-02-21)
 
 
 ### Bug Fixes

docs/user/config/compilerHost.md

@@ -0,0 +1,93 @@
+---
+title: Compiler Host option
+---
+
+By default `ts-jest` uses TypeScript `LanguageService` API in the context of a project (yours), with full type-checking and features.
+But TypeScript `Program` can also be used to achieve the same behavior as `LanguageService`.
+That's what the `compilerHost` option (which defaults to `false`) does.
+
+There are 2 types of TypeScript `Program`, one is `Incremental Program` which is only available from TypeScript 3.4 
+and the other one is normal `Program`.
+
+By default `ts-jest` uses `Incremental Program` if `compilerHost` is enabled. The priority of using TypeScript APIs in `ts-jest`
+as below:
+- Default TypeScript API is `LanguageService`.
+- `compilerHost` is enabled:
+    - `incremental` is enabled (**default**): use TypeScript `Incremental Program`.
+    - `incremental` is disabled: use TypeScript `Program`.
+- `isolatedModules` is enabled, use TypeScript transpile modules.
+
+Here is how to enable `ts-jest` to compile using TypeScript `Program`
+
+### Example
+
+<div class="row"><div class="col-md-6" markdown="block">
+
+```js
+// jest.config.js
+module.exports = {
+  // [...]
+  globals: {
+    'ts-jest': {
+      compilerHost: true,
+      incremental: false,
+    }
+  }
+};
+```
+
+</div><div class="col-md-6" markdown="block">
+
+```js
+// OR package.json
+{
+  // [...]
+  "jest": {
+    "globals": {
+      "ts-jest": {
+        "compilerHost": true,
+        "incremental": false
+      }
+    }
+  }
+}
+```
+
+</div></div>
+
+
+Here is how to enable `ts-jest` to compile using TypeScript `IncrementalProgram`
+
+### Example
+
+<div class="row"><div class="col-md-6" markdown="block">
+
+```js
+// jest.config.js
+module.exports = {
+  // [...]
+  globals: {
+    'ts-jest': {
+      compilerHost: true
+    }
+  }
+};
+```
+
+</div><div class="col-md-6" markdown="block">
+
+```js
+// OR package.json
+{
+  // [...]
+  "jest": {
+    "globals": {
+      "ts-jest": {
+        "compilerHost": true
+      }
+    }
+  }
+}
+```
+
+</div></div>

docs/user/config/index.md

@@ -220,6 +220,7 @@ npx ts-jest config:migrate package.json
 [compiler]: compiler
 [tsConfig]: tsConfig
 [isolatedModules]: isolatedModules
+[compilerHost]: compilerHost
 [diagnostics]: diagnostics
 [babelConfig]: babelConfig
 [stringifyContentPathRegex]: stringifyContentPathRegex

e2e/__cases__/compiler-host/main.spec.ts

@@ -0,0 +1,6 @@
+import { g } from './main'
+
+it('should pass', () => {
+  const x: string = g(5)
+  expect(x).toBe(5)
+})

e2e/__cases__/compiler-host/main.ts

@@ -0,0 +1 @@
+export const g = (v: number) => v

e2e/__cases__/composite/foo.spec.ts

@@ -6,5 +6,7 @@ export enum PackageSets {
   // invalid
   unsupportedVersion = 'with-unsupported-version',
 }
-export const allValidPackageSets = [PackageSets.default, PackageSets.babel7, PackageSets.babel7StringConfig, PackageSets.typescript2_7]
-export const allPackageSetsWithPreset = [PackageSets.default, PackageSets.babel7, PackageSets.babel7StringConfig, PackageSets.typescript2_7]
+export const allValidPackageSets = [PackageSets.default, PackageSets.babel7, PackageSets.babel7StringConfig, PackageSets.typescript2_7],
+  allPackageSetsWithPreset = [PackageSets.default, PackageSets.babel7, PackageSets.babel7StringConfig, PackageSets.typescript2_7],
+  allPackageSetsWithProgram = [PackageSets.default, PackageSets.babel7, PackageSets.babel7StringConfig],
+  allPackageSetsWithoutProgram = [PackageSets.typescript2_7, PackageSets.unsupportedVersion]

e2e/__cases__/composite/tsconfig.json

@@ -32,7 +32,8 @@
       "ts-jest": {
         "diagnostics": true,
         "tsConfig": "<rootDir>/tsconfig.json",
-        "compilerHost": true
+        "compilerHost": true,
+        "incremental": true
       }
     }
   },