add help command-line argument

README.md

@@ -27,6 +27,12 @@ Contributions are welcome! Open a pull request to fix a bug, or open an issue to
   cat sample.json | node json-to-go.js
   ```
 
+- For more options, check the help page
+
+  ```sh
+  node json-to-go.js --help
+  ```
+
 ### Credits
 
 JSON-to-Go is brought to you by Matt Holt ([mholt6](https://twitter.com/mholt6)).

json-to-go.js

@@ -524,6 +524,22 @@ if (typeof module != 'undefined') {
 			process.stdout.write(output.go)
 		}
 
+		function printHelp() {
+			console.log(`\
+Usage: node json-to-go.js [OPTION]... [FILE]
+Convert json to go file and prints the result on stdout.
+
+Optional arguments:
+	--help               Print this help page
+	--all-omitempty      Make all fields "omitempty" (Default: false)
+	--examples           Add examples to go struct. Currently only works without flatten. (Default: false)
+	--flatten            Flatten go struct (Default: true)
+	--typename=NAME      Use a specific name for typename (Default: "AutoGenerated")
+
+All arguments can be inverted by specifing "--no-...", for example "--no-examples".
+		`)
+		}
+
 		process.argv.forEach((val, index) => {
 			if (index < 2)
 				return
@@ -559,8 +575,12 @@ if (typeof module != 'undefined') {
 				case "all-omitempty":
 					 options.allOmitempty = argument.value
 					 break
+				case "help":
+					printHelp()
+					process.exit(0)
 				default:
 					console.error(`Unexpected argument ${val} received`)
+					printHelp()
 					process.exit(1)
 			}
 		})