https://github.com/dggriffin/hubot-jstips

A hubot script that grabs and displays the latest jstip.
https://github.com/dggriffin/hubot-jstips

Last synced: 3 months ago
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A hubot script that grabs and displays the latest jstip.

• Host: GitHub
• URL: https://github.com/dggriffin/hubot-jstips
• Owner: dggriffin
• License: mit
• Created: 2016-01-20T13:31:34.000Z (almost 9 years ago)
• Default Branch: master
• Last Pushed: 2022-07-29T02:24:24.000Z (over 2 years ago)
• Last Synced: 2024-06-30T22:59:52.873Z (5 months ago)
• Language: CoffeeScript
• Size: 9.77 KB
• Stars: 9
• Watchers: 2
• Forks: 2
• Open Issues: 1
• Metadata Files:
  • Readme: README.md
  • License: LICENSE

Awesome Lists containing this project

• jstips - Hubot

README

        
# hubot-jstips



A hubot script that grabs and displays the latest jstip from https://github.com/loverajoel/jstips.

See [`src/jstips.coffee`](src/jstips.coffee) for full documentation.

## Installation

In hubot project repo, run:

`npm install hubot-jstips --save`

Then add **hubot-jstips** to your `external-scripts.json`:

```json

["hubot-jstips"]

```

## Sample Interaction

```

user1>> hubot jstip

hubot>> 

#18 - Rounding the fast way

2016-01-18 by pklinger

Today's tip is about performance. Ever came across the double tilde ~~ operator? It is sometimes also called the double NOT bitwise operator. You can use it as a faster substitute for Math.floor(). Why is that?

One bitwise shift ~ transforms the 32 bit converted input into -(input+1). The double bitwise shift therefore transforms the input into -(-(input + 1)+1) making it a great tool to round towards 0. For numeric input, it therefore mimics the Math.ceil() for negative and Math.floor() for positive input. On failure, 0 is being returned, which might come in handy sometimes instead of Math.floor() return value NaN on failure.

// single ~

console.log(~1337)    // -1338

// numeric input

console.log(~~47.11)  // -> 47

console.log(~~-12.88) // -> -12

console.log(~~1.9999) // -> 1

console.log(~~3)      // -> 3

// on failure

console.log(~~[]) // -> 0

console.log(~~NaN)  // -> 0

console.log(~~null) // -> 0

// greater than 32 bit integer fails

console.log(~~(2147483647 + 1) === (2147483647 + 1)) // -> 0

Although ~~ may perform better, for the sake of readability please use Math.floor().

```