Mr Branding

Thursday, June 14, 2018

What’s New in ES2018

In this article, I’ll cover the new features of JavaScript introduced via ES2018 (ES9), with examples of what they’re for and how to use them.

JavaScript (ECMAScript) is an ever-evolving standard implemented by many vendors across multiple platforms. ES6 (ECMAScript 2015) was a large release which took six years to finalize. A new annual release process has been formulated to streamline the process and add features quicker. ES9 (ES2018) is the latest iteration at the time of writing.

Technical Committee 39 (TC39) consists of parties including browser vendors who meet to push JavaScript proposals along a strict progression path:

Stage 0: strawman -
The initial submission of ideas.

Stage 1: proposal -
A formal proposal document championed by at least once member of TC39 which includes API examples.

Stage 2: draft -
An initial version of the feature specification with two experimental implementations.

Stage 3: candidate -
The proposal specification is reviewed and feedback is gathered from vendors.

Stage 4: finished -
The proposal is ready for inclusion in ECMAScript but may take longer to ship in browsers and Node.js.

ES2016

ES2016 proved the standardization process by adding just two small features:

The array includes() method, which returns true or false when a value is contained in an array, and
The a ** b exponentiation operator, which is identical to Math.pow(a, b).

ES2017

ES2017 provided a larger range of new features:

Async functions for a clearer Promise syntax
Object.values() to extract an array of values from an object containing name–value pairs
Object.entries(), which returns an array of sub-arrays containing the names and values in an object
Object.getOwnPropertyDescriptors() to return an object defining property descriptors for own properties of another object (.value, .writable, .get, .set, .configurable, .enumerable)
padStart() and padEnd(), both elements of string padding
trailing commas on object definitions, array declarations and function parameter lists
SharedArrayBuffer and Atomics for reading from and writing to shared memory locations (disabled in response to the Spectre vulnerability).

Refer to What’s New in ES2017 for more information.

ES2018

ECMAScript 2018 (or ES9 if you prefer the old notation) is now available. The following features have reached stage 4, although working implementations will be patchy across browsers and runtimes at the time of writing.

Asynchronous Iteration

At some point in your async/await journey, you’ll attempt to call an asynchronous function inside a synchronous loop. For example:

async function process(array) {
  for (let i of array) {
    await doSomething(i);
  }
}

It won’t work. Neither will this:

async function process(array) {
  array.forEach(async i => {
    await doSomething(i);
  });
}

The loops themselves remain synchronous and will always complete before their inner asynchronous operations.

ES2018 introduces asynchronous iterators, which are just like regular iterators except the next() method returns a Promise. Therefore, the await keyword can be used with for … of loops to run asynchronous operations in series. For example:

async function process(array) {
  for await (let i of array) {
    doSomething(i);
  }
}

The post What’s New in ES2018 appeared first on SitePoint.

by Craig Buckler via SitePoint

Debugging with Truffle CLI

Debuggers have been crucial software development tools for over thirty years.

A modern debugger enables us to:

run the code line-by-line
set breakpoints in the code
put conditions on the breakpoints
evaluate expressions during runtime.

Most modern debuggers are also highly integrated into development environments of languages they are serving. They enable setting breakpoints by clicking on line numbers, evaluating expressions by hovering over variables, writing conditional breakpoints in the code comments … and so on.

So what is the state of Solidity smart contract debugging and debuggers?

Solidity Debugger

As with most blockchain things, we’re still in the infancy stage. The basic debuggers are available (and advancing at a rapid pace), but no editor integrations are here yet, and the debugger heavily relies on the framework of choice.

In this article, we’ll be exploring the Solidity debugger bundled with the Truffle Suite.

Getting Started

First, we’ll need to install all the required tools. Luckily for us, the Truffle framework is very well integrated, so we’ll just need to install it.

First, install Node.js and NPM. After you’ve installed Node, you can verify that it’s installed by checking the version of the tool like this:

➜  ~ node -v
v10.2.1
➜  ~ npm -v
5.6.0

If your Node is up and running, let’s install the Truffle framework. This is made simple enough by the usage of npm, so just run this:

npm install -g truffle

You can check whether the install was successful by checking the version:

truffle version
Truffle v4.1.11 (core: 4.1.11)
Solidity v0.4.24 (solc-js)

Setting Up the Project

Now that you have Truffle all set up, let’s create a new (empty) Truffle project. Open your terminal, position yourself into a desired directory and run truffle init. The output should be similar to this:

truffle init
Downloading...
Unpacking...
Setting up...
Unbox successful. Sweet!

Commands:

  Compile:        truffle compile
  Migrate:        truffle migrate
  Test contracts: truffle test

After you’ve done this, you should have a contract structure similar to this:

.
├── contracts
│   └── Migrations.sol
├── migrations
│   └── 1_initial_migration.js
├── test
├── truffle-config.js
└── truffle.js

Now open the truffle.js file and put the following data into it:

module.exports = {
  networks: {
      development: {
          port: 9545,
          host: "127.0.0.1",
          network_id: "*"
      }
  }
};

Save the file and run truffle develop. You should get an output similar to this:

truffle develop
Truffle Develop started at http://127.0.0.1:9545/

Accounts:
(0) 0x627306090abab3a6e1400e9345bc60c78a8bef57
(1) 0xf17f52151ebef6c7334fad080c5704d77216b732
(2) 0xc5fdf4076b8f3a5357c5e395ab970b5b54098fef
(3) 0x821aea9a577a9b44299b9c15c88cf3087f3b5544
(4) 0x0d1d4e623d10f9fba5db95830f7d3839406c6af2
(5) 0x2932b7a2355d6fecc4b5c0b6bd44cc31df247a2e
(6) 0x2191ef87e392377ec08e7c08eb105ef5448eced5
(7) 0x0f4f2ac550a1b4e2280d04c21cea7ebd822934b5
(8) 0x6330a553fc93768f612722bb8c2ec78ac90b3bbc
(9) 0x5aeda56215b167893e80b4fe645ba6d5bab767de

Private Keys:
(0) c87509a1c067bbde78beb793e6fa76530b6382a4c0241e5e4a9ec0a0f44dc0d3
(1) ae6ae8e5ccbfb04590405997ee2d52d2b330726137b875053c36d94e974d162f
(2) 0dbbe8e4ae425a6d2687f1a7e3ba17bc98c673636790f1b8ad91193c05875ef1
(3) c88b703fb08cbea894b6aeff5a544fb92e78a18e19814cd85da83b71f772aa6c
(4) 388c684f0ba1ef5017716adb5d21a053ea8e90277d0868337519f97bede61418
(5) 659cbb0e2411a44db63778987b1e22153c086a95eb6b18bdf89de078917abc63
(6) 82d052c865f5763aad42add438569276c00d3d88a2d062d36b2bae914d58b8c8
(7) aa3680d5d48a8283413f7a108367c7299ca73f553735860a87b08f39395618b7
(8) 0f62d96d6675f32685bbdb8ac13cda7c23436f63efbb9d07700d8669ff12b7c4
(9) 8d5366123cb560bb606379f90a0bfd4769eecc0557f1b362dcae9012b548b1e5

Mnemonic: candy maple cake sugar pudding cream honey rich smooth crumble sweet treat

⚠️  Important ⚠️  : This mnemonic was created for you by Truffle. It is not secure.
Ensure you do not use it on production blockchains, or else you risk losing funds.

This started an instance of the Truffle development blockchain backed by ganache-cli (former TestRPC).

The post Debugging with Truffle CLI appeared first on SitePoint.

by Mislav Javor via SitePoint

Full Image Reveal Effect with TweenMax Animation

Today we’d like to share a simple fullscreen image reveal effect with you. The idea is to have an inital thumbnails layout at the bottom of the page and then animate the items when we click them. A covering element comes sliding in and when it moves out, the fullscreen image view is shown behind. We are using TweenMax for the animations.

The post Full Image Reveal Effect with TweenMax Animation appeared first on Best jQuery.

by Admin via Best jQuery