docs: add init documentation (react-native-community#347)

* docs: add init documentation

* docs: add mentions in other files

* docs: revert

* Update docs/init.md

Co-Authored-By: Esemesek <[email protected]>

README.md

@@ -18,6 +18,7 @@ This CLI is intended to be used with a certain version of React Native. You'll f
 ## Documentation
 
 - [commands](./docs/commands.md)
+- [init](./docs/init.md)
 - [autolinking](./docs/autolinking.md)
 - [plugins](./docs/plugins.md)
 
@@ -48,7 +49,9 @@ npx react-native init MyApp
 
 You'll need to install a global module [`react-native-cli`](./packages/global-cli) and follow instructions there.
 
-We strongly encourage you to **only use global `react-native-cli` for bootstrapping new projects**. Use local version for everything else.
+> We strongly encourage you to **only use global `react-native-cli` for bootstrapping new projects**. Use local version for everything else.
+
+You can find out more about init command from the [documentation](./docs/init.md)
 
 ## Usage in an existing React Native project
 

docs/commands.md

@@ -121,7 +121,7 @@ Usage:
 react-native init <projectName> [options]
 ```
 
-Initialize new React Native project.
+Initialize new React Native project. You can find out more use cases in [init docs](./init.md).
 
 #### Options
 

docs/init.md

@@ -0,0 +1,81 @@
+# Initializing new project
+
+There are couple of ways to initialize new React Native projects.
+
+### For `[email protected]` or greater
+
+#### Using `npx` utility:
+
+```sh
+npx react-native init ProjectName
+```
+
+> Note: If you have both `yarn` and `npm` installed on your machine, React Native CLI will always try to use `yarn`, so even if you use `npx` utility, only `react-native` executable will be installed using `npm` and the rest of the work will be delegated to `yarn`. You can force usage of `npm` adding `--npm` flag to the command.
+
+> Note: for Yarn users, `yarn dlx` command similar to `npx` will be featured in Yarn 2.0: https://github.com/yarnpkg/berry/pull/40 so we’ll be able to use it in a similar fashion.
+
+#### Installing `react-native` and invoking `init` command:
+
+```sh
+yarn init && yarn add react-native && yarn react-native init ProjectName
+```
+
+#### Initializing project with custom version of `react-native`:
+
+```sh
+# This will use the latest init command but will install react-native@VERSION and use its template
+npx react-native init ProjectName --version ${VERSION}
+
+# This will use init command from react-native@VERSION
+npx react-native@${VERSION} init ProjectName
+```
+
+#### Initializing project with custom template.
+
+In following examples `TEMPLATE_NAME` can be either:
+- Full package name, eg. `react-native-template-typescript`.
+- Shorthand name of template, eg. `typescript`.
+- Absolute path to directory containing template, eg. `file:///Users/username/project/some-template`.
+
+```sh
+# This will initialize new project using template from TEMPLATE_NAME package
+npx react-native init ProjectName --template ${TEMPLATE_NAME}
+
+# This will initialize new project using init command from react-native@VERSION but will use TEMPLATE_NAME custom template
+npx react-native@${VERSION} init ProjectName --template ${TEMPLATE_NAME}
+```
+
+You can force usage of `npm` if you have both `yarn` and `npm` installed on your machine:
+```sh
+npx react-native init ProjectName --npm
+```
+
+### For older `react-native` versions
+
+Using legacy `react-native-cli` package:
+
+```sh
+yarn global add react-native-cli
+react-native init ProjectName
+```
+
+> Note: It is not recommended, but you can also use legacy `react-native-cli` package to initialize projects using latest `react-native` versions.
+
+# Creating custom template
+
+Every custom template needs to have configuration file called `template.config.js` in the root of the project:
+
+```js
+module.exports = {
+  // Placeholder name that will be replaced in package.json, index.json, android/, ios/ for a project name.
+  placeholderName: "ProjectName",
+
+  // Directory with the template which will be copied and processed by React Native CLI. Template directory should have package.json with all dependencies specified, including `react-native`.
+  templateDir: "./template",
+
+  // Path to script, which will be executed after initialization process, but before installing all the dependencies specified in the template.
+  postInitScript: "./script.js",
+};
+```
+
+You can find example custom template [here](https://github.com/Esemesek/react-native-new-template).

packages/cli/src/commands/init/init.js

@@ -106,7 +106,7 @@ async function createFromReactNativeTemplate(
   try {
     if (semver.valid(version) && !semver.gte(version, '0.60.0')) {
       throw new Error(
-        'Cannot use React Native CLI to initialize project with version less than 0.60.0',
+        'Cannot use React Native CLI to initialize project with version lower than 0.60.0',
       );
     }