The following summarises the learnings of migrating from the async promises module to ES6 promises, with a simple sample.
Async is a library containing a bunch of async utility functions like
async.parallel : To execute a bunch of async tasks in parallel.async.waterfall: To execute a bunch of async tasks sequentially.####The example had a combo of both:
| <!DOCTYPE html> | |
| <html> | |
| <head> | |
| <style> | |
| body{ | |
| width: 960px; | |
| margin: 0 auto; | |
| padding: 0; | |
| } | |
| * { |
| // The Binary tree will be built with the Tree Node representation (Linked representation) | |
| function TreeNode(val) { | |
| this.val = val; | |
| this.left = this.right = null; | |
| } | |
| // Convert a given array of data values into a binary tree representation | |
| // This assumes a 0 index array | |
| // So for an index i, the Left Child would be at 2(i) + 1 | |
| // The right Child will be at 2(i) + 2 |
| // Post Order traversal => Left - Right - Data | |
| // L-R-D | |
| // Possible combinations | |
| // 1. L-D | |
| // Only Left exists. Right is absent. Since the Node has to be processed after the | |
| // LEFT is processed, its pushed into the stack for later processing. | |
| // Continue process the LEFT subtree. | |
| // 2. R-D | |
| // Only Right exists. Left is absent. Since the Node has to be processed after the | |
| // RIGHT is processed, its pushed into the stack for later processing. |
| // A pre-order traversal means Data - LEFT - RIGHT | |
| // So, the possible combinations are | |
| // 1. D-L | |
| // No Right => Process Node and proceed with Left SubTree | |
| // No need to push into a stack for later processing (as there is no RIGHT) | |
| // 2. D-R | |
| // No Left => Process Node and proceed with Right SubTree. | |
| // No need to push into a stack for later processing (as RIGHT exists) | |
| // and RIGHT is being processed currently (due to absence of a LEFT) |
| // inOrder Traversal | |
| // Left - Data - Right | |
| // Note that the Data is processed only after LEFT is processed. | |
| // Same way, Right is processed only after Left and Data are processed. | |
| // So, the key here is, the moment a LEFT occurs, push it into the stack for later | |
| // processing. | |
| // So, when a Node is popped off the stack, its not guaranteed to have a RIGHT. | |
| // So, when we hit a LEAF node, we pop the immediate previous ancestor, but, | |
| // This is not guaranteed to have a RIGHT. Just process it. |
| const UploaderMachine = Machine( | |
| { | |
| strict: true, | |
| id: "uploader-machine", | |
| context: { | |
| progress: false, | |
| progressDataModel: { | |
| progressMsg: "", |
| require('marko/node-require').install(); | |
| const http = require('http'); | |
| const server = require('http').createServer(); | |
| const port = 8080; | |
| const indexTemplate = require('./index.marko'); | |
| server.on('request', (req, res) => { | |
| indexTemplate.render({ | |
| name: 'Frank', | |
| count: 30, | |
| colors: ['red', 'green', 'blue'] |
| { | |
| "name": "marko3-http", | |
| "version": "0.0.0", | |
| "description": "Example of using Marko with a simple Node.js HTTP server", | |
| "main": "server.js", | |
| "scripts": { | |
| "test": "echo \"Error: no test specified\" && exit 1" | |
| }, | |
| "keywords": [ | |
| "marko", |
| <html> | |
| <head></head> | |
| <body> | |
| <p>Hello ${data.name}! You have ${data.count} messages!</p> | |
| <ul if(data.colors && data.colors.length)> | |
| <li style="color: ${color}" for(color in data.colors)>${color}</li> | |
| </ul> | |
| <include("./footer.marko") name=data.name/> | |
| </body> | |
| </html> |