Tutorial on building frontend apps with JS SDK

building-a-frontend-with-js-sdk.md

@@ -1,29 +1,247 @@
 # Building a Frontend with JS-SDK
 
-JS sdk provies 
+Fluence provides means to connect to the network from a javascript environment. It is currently tested to work in nodejs and modern browsers. 
 
-fluence provides bla bla bla. You can use it in both browser and nodejs. Everything is writtein in typescript which is good
+To create an application you will need two main building blocks: the JS SDK itself and the aqua compiler. Both of them are provided in a form npm packages. JS SDK wraps the air interpreter and provides a connection to the network. There is low-level api for executing air scripts and registering for service calls handlers. Aqua compiler allows to write code in aqua language and compile it into typescript code which can be directly used with the SDK.
 
-basic
+Even though all the logic could be programmed by hand with raw air it is strongly recommended to use aqua.
 
-- init your package
-- install sdk
-- install aqua
-- create build script
-- write aqua code
-- compile
-- get generated file
-- create client
-- run the function
+## Basic usage
 
-advanced
+As previously said you can use fluence with any frontend or nodejs framework. JS SDK could be as any other npm library. For the purpose of the demo we  will init a bare-bones nodejs package and show you the steps needed install JS SDK and aqua compiler. Feel free to use the tool most suitable for the framework used in application, the installation process should be roughly the same
 
-- registering custom services
+### 1. Start with npm package
+
+For the purpose of the demo we will use a very minimal npm package with typescript support:
+
+```
+src
+ ┗ index.ts           (1)
+package.json          (2)
+tsconfig.json
+```
+
+index.ts (1):
+
+```typescript
+async function main() {
+  console.log("Hello, world!");
+}
+
+main();
+```
+
+package.json (2):
+
+```json
+{
+  "name": "demo",
+  "version": "1.0.0",
+  "description": "",
+  "main": "index.js",
+  "scripts": {
+    "exec": "node -r ts-node/register src/index.ts"
+  },
+  "author": "",
+  "license": "ISC",
+  "devDependencies": {
+    "ts-node": "^9.1.1",
+    "typescript": "^4.2.4"
+  }
+}
+
+```
+
+Let's test if it works:
+
+```bash
+$ npm install
+$ npm run exec
+```
+
+The following should be printed
+
+```bash
+$ npm run exec
+
+> demo@1.0.0 exec C:\work\demo
+> node -r ts-node/register src/index.ts
+
+Hello, world!
+$ C:\work\demo>
+```
+
+### 2. Setting JS SDK and connecting to Fluence network
+
+Install the dependencies, you will need these two packages.
+
+```bash
+npm install @fluencelabs/fluence @fluencelabs/fluence-network-environment
+```
+
+The first one is the SDK itself and the second is a maintained list of Fluence networks and nodes to connect to.
+
+All of the communication with the Fluence network is done by using `FluenceClient`. You can create one with `createClient` function. The client encapsulates air interpreter and connects to the network through the relay. Currently any node in the network can be used a relay. 
+
+```typescript
+import { createClient } from "@fluencelabs/fluence";
+import { testNet } from "@fluencelabs/fluence-network-environment";
+
+async function main() {
+  const client = await createClient(testNet[1]);
+  console.log("Is client connected: ", client.isConnected);
+
+  await client.disconnect();
+}
+
+main();
+
+```
+
+Let's try it out:
+
+```bash
+$ npm run exec
+
+> demo@1.0.0 exec C:\work\demo
+> node -r ts-node/register src/index.ts
+
+Is client connected:  true
+$
+
+```
+
+**Note**: typically you should have a single instance`FluenceClient` per application since it represents it's identity in the network. You are free to store the instance anywhere you like.
+
+### 3. Setting up aqua compiler
+
+Aqua is the proffered language for the Fluence network. It can be used with javascript-based environments via npm package. 
+
+**Warning: the package requires java to be installed (it will call "java -jar ... ") **
+
+```bash
+npm install --save-dev @fluencelabs/aqua-cli
+```
+
+We will also need the standard library for the language
+
+```
+npm install --save-dev @fluencelabs/aqua-lib
+```
+
+Let's add our first aqua file:
+
+```
+aqua                   (1)
+ ┗ demo.aqua           (2)
+node_modules
+src
+ ┣ compiled            (3)
+ ┗ index.ts     
+package-lock.json
+package.json          
+tsconfig.json
+```
+
+Add two directories, one for aqua sources (1) and another for the typescript output (3)
+
+Create a new text file called `demo.aqua` (2):
+
+```
+import "@fluencelabs/aqua-lib/builtin.aqua"
+
+func demo(nodePeerId: PeerId) -> []string:
+    on nodePeerId:
+        res <- Peer.identify()
+    <- res.external_addresses
+```
+
+This script will gather the list of external addresses from some node in the network. For more information about the aqua language refer to the aqua documentation.
+
+The aqua code can now be compiled by using the compiler CLI. We suggest adding a script to the package.json file like so:
+
+```json
+...
+  "scripts": {
+    "exec": "node -r ts-node/register src/index.ts",
+    "compile-aqua": "aqua-cli -i ./aqua/ -o ./src/compiled"
+  },
+...
+```
+
+Run the compiler:
+
+```bash
+npm run compile-aqua
+```
+
+A typescript file should be generated like so:
+
+```
+aqua                   
+ ┗ demo.aqua           
+node_modules
+src
+ ┣ compiled
+ ┃ ┗ demo.ts           <--
+ ┗ index.ts     
+package-lock.json
+package.json          
+tsconfig.json
+```
+
+### 4. Consuming the compiled code
+
+Using the code generated by the compiler is as easy as calling a function. The compiler generates all the boilerplate needed to send a particle into the network and wraps it into a single call. Note that all the type information and therefore type checking and code completion facilities are there!
+
+Let's do it!
+
+```typescript
+import { createClient } from "@fluencelabs/fluence";
+import { testNet } from "@fluencelabs/fluence-network-environment";
+
+import { demo } from "./compiled/demo"; // import the generated file
+
+async function main() {
+  const client = await createClient(testNet[1]);
+  console.log("Is client connected: ", client.isConnected);
+
+  const otherNode = testNet[2].peerId;
+  const addresses = await demo(client, otherNode); // call it like a normal function in typescript
+  console.log(`Node ${otherNode} is connected to: ${addresses}`);
+
+  await client.disconnect();
+}
+
+main();
+
+```
+
+if everything is fine you have similar result:
+
+```
+$ npm run exec
+
+> demo@1.0.0 exec C:\work\demo
+> node -r ts-node/register src/index.ts
+
+Is client connected:  true
+Node 12D3KooWHk9BjDQBUqnavciRPhAYFvqKBe4ZiPPvde7vDaqgn5er is connected to: /ip4/138.197.189.50/tcp/7001,/ip4/138.197.189.50/tcp/9001/ws
+
+$
+```
 
 
 
-references
+## Advanced usage
 
-- aqua playground
-- fluentpad
+Fluence JS SDK gives options to register own handlers for aqua vm service calls
 
+**TBD**
+
+
+
+## References
+
+- For the list of compiler options see: https://github.com/fluencelabs/aqua
+- Repository with additional examples: https://github.com/fluencelabs/aqua-playground