Merge pull request microsoft#745 from vkrol/patch-1

Add `--preserveWatchOutput` flag

Author: mhegazy

pages/Compiler Options.md

@@ -58,6 +58,7 @@ Option                                         | Type      | Default
 `paths`<sup>[2]</sup>                          | `Object`  |                                | List of path mapping entries for module names to locations relative to the `baseUrl`. See [Module Resolution documentation](./Module Resolution.md#path-mapping) for more details.
 `--preserveConstEnums`                         | `boolean` | `false`                        | Do not erase const enum declarations in generated code. See [const enums documentation](https://github.com/Microsoft/TypeScript/blob/master/doc/spec.md#94-constant-enum-declarations) for more details.
 `--preserveSymlinks`                            | `boolean` | `false`                       | Do not resolve symlinks to their real path; treat a symlinked file like a real one.
+`--preserveWatchOutput`                        | `boolean` | `false`                        | Keep outdated console output in watch mode instead of clearing the screen
 `--pretty`<sup>[1]</sup>                       | `boolean` | `false`                        | Stylize errors and messages using color and context.
 `--project`<br/>`-p`                           | `string`  |                                | Compile a project given a valid configuration file.<br/>The argument can be a file path to a valid JSON configuration file, or a directory path to a directory containing a `tsconfig.json` file.<br/>See [tsconfig.json](./tsconfig.json.md) documentation for more details.
 `--reactNamespace`                             | `string`  | `"React"`                      | DEPRECATED. Use `--jsxFactory` instead.<br/>Specifies the object invoked for `createElement` and `__spread` when targeting `"react"` JSX emit.