feat: allow ast transformers to take in addl opts, fix #1942

docs/user/config/astTransformers.md

@@ -7,13 +7,15 @@ TypeScript AST transformers and provide them to `ts-jest` to include into compil
 
 The option is `astTransformers` and it allows ones to specify which 3 types of TypeScript AST transformers to use with `ts-jest`:
 
-- `before` means your transformers get run before TS ones, which means your transformers will get raw TS syntax 
-instead of transpiled syntax (e.g `import` instead of `require` or `define` ).
+- `before` means your transformers get run before TS ones, which means your transformers will get raw TS syntax
+  instead of transpiled syntax (e.g `import` instead of `require` or `define` ).
 - `after` means your transformers get run after TS ones, which gets transpiled syntax.
 - `afterDeclarations` means your transformers get run during `d.ts` generation phase, allowing you to transform output type declarations.
 
 ### Examples
 
+#### Basic Transformers
+
 <div class="row"><div class="col-md-6" markdown="block">
 
 ```js
@@ -25,9 +27,52 @@ module.exports = {
       astTransformers: {
         before: ['my-custom-transformer'],
       },
+    },
+  },
+}
+```
+
+</div><div class="col-md-6" markdown="block">
+
+```js
+// OR package.json
+{
+  // [...]
+  "jest": {
+    "globals": {
+      "ts-jest": {
+        astTransformers: {
+          "before": ["my-custom-transformer"]
+        }
+      }
     }
   }
-};
+}
+```
+
+</div></div>
+
+#### Configuring transformers with options
+
+<div class="row"><div class="col-md-6" markdown="block">
+
+```js
+// jest.config.js
+module.exports = {
+  // [...]
+  globals: {
+    'ts-jest': {
+      astTransformers: {
+        before: [
+          {
+            path: 'my-custom-transformer-that-needs-extra-opts',
+            options: {},
+          },
+        ],
+      },
+    },
+  },
+}
 ```
 
 </div><div class="col-md-6" markdown="block">
@@ -40,7 +85,10 @@ module.exports = {
     "globals": {
       "ts-jest": {
         astTransformers: {
-          "before": ["my-custom-transformer"]
+          "before": [{
+            path: 'my-custom-transformer-that-needs-extra-opts',
+            options: {}
+          }]
         }
       }
     }
@@ -55,9 +103,9 @@ module.exports = {
 `ts-jest` is able to expose transformers for public usage to provide the possibility to opt-in/out for users. Currently
 the exposed transformers are:
 
-- `path-mapping` convert alias import/export to relative import/export path base on `paths` in `tsconfig`. 
-This transformer works similar to `moduleNameMapper` in `jest.config.js`. When using this transformer, one might not need
-`moduleNameMapper` anymore.
+- `path-mapping` convert alias import/export to relative import/export path base on `paths` in `tsconfig`.
+  This transformer works similar to `moduleNameMapper` in `jest.config.js`. When using this transformer, one might not need
+  `moduleNameMapper` anymore.
 
 #### Example of opt-in transformers
 
@@ -72,9 +120,9 @@ module.exports = {
       astTransformers: {
         before: ['ts-jest/dist/transformers/path-mapping'],
       },
-    }
-  }
-};
+    },
+  },
+}
 ```
 
 </div><div class="col-md-6" markdown="block">
@@ -97,7 +145,6 @@ module.exports = {
 
 </div></div>
 
-
 ### Writing custom TypeScript AST transformers
 
 To write a custom TypeScript AST transformers, one can take a look at [the one](https://github.com/kulshekhar/ts-jest/tree/master/src/transformers) that `ts-jest` is using.

src/config/__snapshots__/config-set.spec.ts.snap

@@ -355,3 +355,14 @@ exports[`tsJest transformers should display deprecation warning message when con
 "[level:40] The configuration for astTransformers as string[] is deprecated and will be removed in ts-jest 27. Please define your custom AST transformers in a form of an object. More information you can check online documentation https://kulshekhar.github.io/ts-jest/user/config/astTransformers
 "
 `;
+
+exports[`tsJest transformers should support transformers with options 1`] = `
+Array [
+  Object {
+    "options": Object {
+      "foo": 1,
+    },
+    "path": Any<String>,
+  },
+]
+`;

src/config/config-set.spec.ts

@@ -161,6 +161,37 @@ describe('tsJest', () => {
       expect(logger.target.lines[1]).toMatchSnapshot()
     })
 
+    it('should support transformers with options', () => {
+      const cs = createConfigSet({
+        jestConfig: {
+          rootDir: 'src',
+          cwd: 'src',
+          globals: {
+            'ts-jest': {
+              astTransformers: {
+                before: [
+                  {
+                    path: 'dummy-transformer',
+                    options: {
+                      foo: 1,
+                    },
+                  },
+                ],
+              },
+            },
+          },
+        } as any,
+        logger,
+        resolve: null,
+      })
+
+      expect(cs.tsJest.transformers.before).toMatchSnapshot([
+        {
+          path: expect.any(String),
+        },
+      ])
+    })
+
     it.each([
       {},
       {