docs: use async/await in 101 example (#1491) (#1495)

Replaces the async npm package with vanilla JavaScript.

License: MIT
Signed-off-by: David Gilbertson <[email protected]>

Author: davidgilbertson

README.md

@@ -97,7 +97,9 @@ This project is available through [npm](https://www.npmjs.com/). To install run
 > npm install ipfs --save
 ```
 
-Requires npm@3 and node@6 or above, tested on OSX & Linux, expected to work on Windows.
+We support both the Current and Active LTS versions of Node.js. Please see [nodejs.org](https://nodejs.org/) for what these currently are.
+
+This project is tested on OSX & Linux, expected to work on Windows.
 
 ### Use in Node.js
 

examples/ipfs-101/1.js

@@ -1,32 +1,22 @@
 'use strict'
 
-const series = require('async/series')
 const IPFS = require('ipfs')
 
 const node = new IPFS()
-let fileMultihash
-
-series([
-  (cb) => node.on('ready', cb),
-  (cb) => node.version((err, version) => {
-    if (err) { return cb(err) }
-    console.log('Version:', version.version)
-    cb()
-  }),
-  (cb) => node.files.add({
+
+node.on('ready', async () => {
+  const version = await node.version()
+
+  console.log('Version:', version.version)
+
+  const filesAdded = await node.files.add({
     path: 'hello.txt',
     content: Buffer.from('Hello World 101')
-  }, (err, filesAdded) => {
-    if (err) { return cb(err) }
-
-    console.log('\nAdded file:', filesAdded[0].path, filesAdded[0].hash)
-    fileMultihash = filesAdded[0].hash
-    cb()
-  }),
-  (cb) => node.files.cat(fileMultihash, (err, data) => {
-    if (err) { return cb(err) }
-
-    console.log('\nFile content:')
-    process.stdout.write(data)
   })
-])
+
+  console.log('Added file:', filesAdded[0].path, filesAdded[0].hash)
+
+  const fileBuffer = await node.files.cat(filesAdded[0].hash)
+
+  console.log('Added file contents:', fileBuffer.toString())
+})

examples/ipfs-101/README.md

@@ -1,80 +1,91 @@
 # IPFS 101, spawn a node and add a file to the IPFS network
 
-In this tutorial, we go through spawning an IPFS node, adding a file and cat'ing the file multihash locally and throught the gateway.
+In this tutorial, we go through spawning an IPFS node, adding a file and cat'ing the file multihash locally and through the gateway.
 
-You can find a complete version of this tutorial in [1.js](./1.js). For this tutorial, you need to install the following dependencies: `ipfs` and `async` using `npm install ipfs async`.
+You can find a complete version of this tutorial in [1.js](./1.js). For this tutorial, you need to install `ipfs` using `npm install ipfs`.
 
 Creating an IPFS instance can be done in one line, after requiring the module, you simply have to:
 
-```JavaScript
+```js
 const IPFS = require('ipfs')
 
 const node = new IPFS()
 ```
 
-We can listen for the `ready` event to learn when the node is ready to be used. In this part, we start using `async/series` to help us manage the async flow. As a test, we are going to check the version of the node.
+We can listen for the `ready` event to learn when the node is ready to be used. Within the ready event, we'll use `async`/`await` to help us manage the async flow.
 
-```JavaScript
+As a test, we are going to check the version of the node.
+
+```js
 const IPFS = require('ipfs')
 
 const node = new IPFS()
 
-series([
-  (cb) => node.on('ready', cb),
-  (cb) => node.version((err, version) => {
-    if (err) { return cb(err) }
-    console.log('Version:', version.version)
-    cb()
-  })
-])
+node.on('ready', async () => {
+  const version = await node.version()
+
+  console.log('Version:', version.version)
+})
 ```
 
+(If you prefer not to use `async`/`await`, you can instead use `.then()` as you would with any promise,
+or pass an [error-first callback](https://nodejs.org/api/errors.html#errors_error_first_callbacks), e.g. `node.version((err, version) => { ... })`)
+
 Running the code above gets you:
 
 ```bash
 > node 1.js
-IPFS Version: 0.25.0
+Version: 0.31.2
 ```
 
-Now lets make it more interesting and add a file to IPFS. We can do it by adding another async call to the series that uses the `node.files.add` call. You can learn about IPFS API for files at [interface-ipfs-core](https://github.com/ipfs/interface-ipfs-core/blob/master/SPEC/FILES.md).
-
-```JavaScript
-// Create the File to add, a file consists of a path + content. More details on
-// https://github.com/ipfs/interface-ipfs-core/blob/master/SPEC/FILES.md
-(cb) => node.files.add({
-  path: 'hello.txt',
-  content: Buffer.from('Hello World')
-}, (err, filesAdded) => {
-  if (err) { return cb(err) }
-
-  // Once the file is added, we get back an object containing the path, the
-  // multihash and the sie of the file
-  console.log('\nAdded file:', filesAdded[0].path, filesAdded[0].hash)
-  fileMultihash = filesAdded[0].hash
-  cb()
+Now let's make it more interesting and add a file to IPFS using `node.files.add`. A file consists of a path and content.
+
+You can learn about the IPFS File API at [interface-ipfs-core](https://github.com/ipfs/interface-ipfs-core/blob/master/SPEC/FILES.md).
+
+```js
+node.on('ready', async () => {
+  const version = await node.version()
+
+  console.log('Version:', version.version)
+  
+  const filesAdded = await node.files.add({
+    path: 'hello.txt',
+    content: Buffer.from('Hello World 101')
+  })
+  
+  console.log('Added file:', filesAdded[0].path, filesAdded[0].hash)
 })
 ```
 
-If you avoid calling that last `cb()`, the program won't exit enabling you to go to an IPFS Gateway and load the printed hash from a gateway. Go ahead and try it!
+You can now go to an IPFS Gateway and load the printed hash from a gateway. Go ahead and try it!
 
 ```bash
 > node 1.js
-Version: 0.25.0
+Version: 0.31.2
 
 Added file: hello.txt QmXgZAUWd8yo4tvjBETqzUy3wLx5YRzuDwUQnBwRGrAmAo
 # Copy that hash and load it on the gateway, here is a prefiled url:
 # https://ipfs.io/ipfs/QmXgZAUWd8yo4tvjBETqzUy3wLx5YRzuDwUQnBwRGrAmAo
 ```
 
-The last step of this tutorial is retrieving the file back using the `cat` 😺 call. Add another step on the series chain that does the following:
+The last step of this tutorial is retrieving the file back using the `cat` 😺 call.
+
+```js
+node.on('ready', async () => {
+  const version = await node.version()
+
+  console.log('Version:', version.version)
+
+  const filesAdded = await node.files.add({
+    path: 'hello.txt',
+    content: Buffer.from('Hello World 101')
+  })
+  
+  console.log('Added file:', filesAdded[0].path, filesAdded[0].hash)
 
-```JavaScript
-(cb) => node.files.cat(fileMultihash, (err, data) => {
-  if (err) { return cb(err) }
+  const fileBuffer = await node.files.cat(filesAdded[0].hash)
 
-  console.log('\nFile content:')
-  // print the file to the terminal and then exit the program
-  process.stdout.write(data)
+  console.log('Added file contents:', fileBuffer.toString())
 })
 ```
 

examples/ipfs-101/package.json

@@ -9,7 +9,6 @@
   "author": "David Dias <[email protected]>",
   "license": "MIT",
   "dependencies": {
-    "async": "^2.6.0",
     "ipfs": "file:../../"
   }
 }