Document support for config.js

.prettierignore

@@ -0,0 +1,4 @@
+dist
+node_modules
+README.md
+*.json

README.md

@@ -45,8 +45,13 @@ polkadot-launch config.json
 ### Configuration File
 
 The required configuration file defines the properties of the network you want to set up.
+You may use a json or a js file.
 
-You can see an example [here](config.json).
+You can see the examples:
+- [config.json](config.json)
+- [config.js](config.js)
+
+You may find the .js alternative more convenient if you need comments, trailing commas or if you prefer do dedup some portions of the config.
 
 #### `relaychain`
 

config.js

@@ -0,0 +1,92 @@
+// Collator flags
+var flags = ["--force-authoring", "--", "--execution=wasm"];
+
+var config = {
+	relaychain: {
+		bin: "./bin/polkadot",
+		chain: "rococo-local",
+		nodes: [
+			{
+				name: "alice",
+				wsPort: 9944,
+				port: 30444,
+			},
+			{
+				name: "bob",
+				wsPort: 9955,
+				port: 30555,
+			},
+			{
+				name: "charlie",
+				wsPort: 9966,
+				port: 30666,
+			},
+			{
+				name: "dave",
+				wsPort: 9977,
+				port: 30777,
+			},
+		],
+		genesis: {
+			runtime: {
+				runtime_genesis_config: {
+					configuration: {
+						config: {
+							validation_upgrade_frequency: 1,
+							validation_upgrade_delay: 1,
+						},
+					},
+				},
+			},
+		},
+	},
+	parachains: [
+		{
+			bin: "./bin/polkadot-collator",
+			id: "200",
+			balance: "1000000000000000000000",
+			nodes: [
+				{
+					wsPort: 9988,
+					port: 31200,
+					name: "alice",
+					flags,
+				},
+			],
+		},
+		{
+			bin: "./bin/polkadot-collator",
+			id: "300",
+			balance: "1000000000000000000000",
+			nodes: [
+				{
+					wsPort: 9999,
+					port: 31300,
+					name: "alice",
+					flags,
+				},
+			],
+		},
+	],
+	simpleParachains: [
+		{
+			bin: "./bin/adder-collator",
+			id: "400",
+			port: "31400",
+			name: "alice",
+			balance: "1000000000000000000000",
+		},
+	],
+	hrmpChannels: [
+		{
+			sender: 200,
+			recipient: 300,
+			maxCapacity: 8,
+			maxMessageSize: 512,
+		},
+	],
+	types: {},
+	finalization: false,
+};
+
+module.exports = config;