Add page for typescript client generator (#764)

* Add page for typescript client generator

* Update client-generator/typescript.md

Co-Authored-By: luca-nardelli <[email protected]>

* Update client-generator/typescript.md

Co-Authored-By: luca-nardelli <[email protected]>

* Remove installation instructions in favor of npx

* Use code blocks instead of indentations in markdown

* Update client-generator/typescript.md

Co-Authored-By: luca-nardelli <[email protected]>

Author: luca-nardelli

client-generator/typescript.md

@@ -0,0 +1,31 @@
+# Typescript Interfaces
+
+The TypeScript Generator allows you to create [TypeScript interfaces](https://www.typescriptlang.org/docs/handbook/interfaces.html) that you can embed in any TypeScript-enabled project (React, Vue.js, Angular..)
+
+To do so, run the client generator:
+
+```bash
+$ npx @api-platform/client-generator -g typescript https://demo.api-platform.com src/ --resource foo
+# Replace the URL by the entrypoint of your Hydra-enabled API
+# "src/" represents where the interfaces will be generated
+# Omit the resource flag to generate files for all resource types exposed by the API
+```
+
+This command parses the Hydra documentation and creates one `.ts` file for each API Resource you have defined in your application, in the `interfaces` subfolder.
+
+NOTE: If you are not sure what the entrypoint is, see [Troubleshooting](troubleshooting.md)
+
+## Example
+
+Assuming you have 2 resources in your application, `Foo` and `Bar`, when you run
+
+```bash
+npx @api-platform/client-generator -g typescript https://demo.api-platform.com src/
+```
+
+you will obtain 2 `.ts` files arranged as following:
+
+* src/
+  * interfaces/
+    * foo.ts
+    * bar.ts