message: docs(preset): usage of all presets + note about testMatch
diff: @@ -6,9 +6,19 @@ The later is preferred since it's more customizable, but it depends on your need
  ## Jest preset
  +### The 3 presets
  +
  +`ts-jest` comes with 3 presets, allowing to cover most of project's base configuration:
  +
  +| Preset name | Description |
  +|---|---|
  +| `ts-jest/presets/default`<br>or `ts-jest` | `ts-jest` will take care of `.ts` and `.tsx` files only, leaving JavaScript files as-is. |
  +| `ts-jest/presets/js-with-ts` | TypeScript and JavaScript file (`.ts`, `.tsx`, `.js` and `.jsx`) will be handled by `ts-jest` (and so TypeScript).<br>You'll need to set `allowJs` to `true` in your `tsconfig.json` file. |
  +| `ts-jest/presets/js-with-babel` | TypeScript files will be handled by `ts-jest`, and JavaScript files will be handled by `babel-jest`. |
  +
  ### Basic usage
  -In most cases, simply adding `preset: 'ts-jest'` to your Jest config should be enough to start using TypeScript with Jest (assuming you did add `ts-jest` to your dev. dependencies of course):
  +In most cases, simply setting the `preset` key to the desired preset name in your Jest config should be enough to start using TypeScript with Jest (assuming you did add `ts-jest` to your dev. dependencies of course):
  <div class="row"><div class="col-md-6" markdown="block">
  @@ -16,6 +26,8 @@ In most cases, simply adding `preset: 'ts-jest'` to your Jest config should be e
  // jest.config.js
  module.exports = {
  // [...]
  + // Replace `ts-jest` with the preset you want to use
  + // from the above list
  preset: 'ts-jest'
  };
  ```
  @@ -27,6 +39,8 @@ module.exports = {
  {
  // [...]
  "jest": {
  + // Replace `ts-jest` with the preset you want to use
  + // from the above list
  "preset": "ts-jest"
  }
  }
  @@ -34,20 +48,26 @@ module.exports = {
  </div></div>
  +**Note:** presets are using `testMatch`, as Jest's does in its defaults. If you want to use `testRegex` instead in your configuration, you MUST set `testMatch` to `null` or Jest will bail.
  +
  ### Advanced
  -The `ts-jest` preset can also be used with other options.
  -If you're already using another preset, you might want only some specific settings from the `ts-jest` preset.
  +Any preset can also be used with other options.
  +If you're already using another preset, you might want only some specific settings from the `ts-jest` chosen preset.
  In this case you'll need to use the JavaScript version of Jest config:
  ```js
  // jest.config.js
  -const { jestPreset: tsJestPreset } = require('ts-jest');
  +const tsJestPresets = require('ts-jest/presets');
  +
  +const preset = tsJestPresets.defaults
  +// const preset = tsJestPresets.jsWithTs
  +// const preset = tsJestPresets.jsWithBabel
  module.exports = {
  // [...]
  transform: {
  - ...tsJestPreset.transform,
  + ...preset.transform,
  // [...]
  }
  }
  