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Need Help: JS array to change a word every 90 days

Asked by Brandon H,

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Grand Master

Brandon H Supervisor

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Hello

 

I'm working on a JavaScript array with several words in it and I want it to cycle to the next word every 90 days (or every 3 months if easier).

 

Say I have an array like the following

  

var word = ['test1', 'test2', 'test3', 'test4'];

 

I'd like to do it by date string so I already have a set of variables setup to show date in the following format:

YYYYMMDD

20171213

 

Any help would be appreciated, I am a bit new to JavaScript and Java in general.

 

edit: current code 

<!doctype html>
<html>
<head>
<meta charset="utf-8">
<title>JavaScript Word Testing</title>
<script>
var word = ['test1', 'test2', 'test3', 'test4'];
var d = new Date();
var day = dom(d);
var m1 = d.getMonth() + 1;
var month = ('0' + m1).slice(-2);
var year = d.getFullYear();

function dom(d) {
	return (d.getDate() < 10 ? '0' : '') + d.getDate();
}

window.onload = function tf() {
	document.getElementById('dateid').innerHTML = year + month + day;
    document.getElementById('wordid').innerHTML = word[0];
};
</script>
</head>

<body>
<p>Current Date: <span id='dateid'></span></p>
<p>word: <span id='wordid'></span></p>
</body>
</html>

 

4 answers to this question

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Grand Master

Seahorsepip Veteran

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Let's start by making a date: 

let date = new Date();

Then let's get our word: 

document.getElementById('wordid').innerHTML = word[Math.round((date.getMonth() + 1) / 3) - 1)]; //Pick a different word every 3 months

As for the readable date string, consider using toLocaleDateString(): 

document.getElementById('dateid').innerHTML = date.toLocaleDateString();

As for the formatting, see the following options documentation: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Date/toLocaleDateString#Using_options

 

 

As for every 30 days instead of every 3 months, see the many solutions/workarounds on stackoverflow: https://stackoverflow.com/questions/8619879/javascript-calculate-the-day-of-the-year-1-366

Or be lazy and use a library like moment.js for everything date related, day of year is as simple as: 

let day = moment().dayOfYear();

Then you simply do: 

document.getElementById('wordid').innerHTML = word[Math.round(day / 30) - 1)]; //Pick a different word every 30 days

 

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Grand Master

DevTech

Posted
Posted
On 12/14/2017 at 4:19 AM, Seahorsepip said:

 

As for every 30 days instead of every 3 months, see the many solutions/workarounds on stackoverflow: https://stackoverflow.com/questions/8619879/javascript-calculate-the-day-of-the-year-1-366

Or be lazy and use a library like moment.js for everything date related, day of year is as simple as: 


let day = moment().dayOfYear();

Then you simply do: 


document.getElementById('wordid').innerHTML = word[Math.round(day / 30) - 1)]; //Pick a different word every 30 days

 

Using a well tested Library is never lazy. It is good engineering. It reduces the chances of bugs and saves time to focus on the main purpose of your app. And date calculations can be crazy akin to rolling your own encryption!

 

For reference, NodaTime is great for .NET and it has been ported to Java as JodaTime:

 

https://nodatime.org/

 

http://www.joda.org/joda-time/

 

For JavaScript, I agree with moment.js

 

https://momentjs.com/

 

 

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Grand Master

Seahorsepip Veteran

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2 hours ago, DevTech said:

Using a well tested Library is never lazy. It is good engineering. It reduces the chances of bugs and saves time to focus on the main purpose of your app. And date calculations can be crazy akin to rolling your own encryption!

 

For reference, NodaTime is great for .NET and it has been ported to Java as JodaTime:

 

https://nodatime.org/

 

http://www.joda.org/joda-time/

 

For JavaScript, I agree with moment.js

 

https://momentjs.com/

 

 

With lazy I was referring to developers using external JS libraries for almost every single line of code resulting in 30 dependencies for 50 lines of code.

Libraries are great but the moment you use libraries like https://www.npmjs.com/package/sum-of-two-numbers you should start getting worried :shiftyninja:

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Grand Master

DevTech

Posted
Posted
9 hours ago, Seahorsepip said:

With lazy I was referring to developers using external JS libraries for almost every single line of code resulting in 30 dependencies for 50 lines of code.

Libraries are great but the moment you use libraries like https://www.npmjs.com/package/sum-of-two-numbers you should start getting worried :shiftyninja:

Yeah but... you made that particular point in the context of Date Calculations which few people realize are a tricky minefield, so it might have been more informative to say something like "if you are one of those minimalists that hate to use libraries, here is an area you should make an exception"

 

But I could have worded my comment better since it is hard to get posts in this sub-forum and quibbling over details when you were providing some great help was mainly stupid on my part.

 

I love that sum function for sheer understated Monty Pythonish afrontery. In keeping with that venerable Bristish tradition it would be nice if we could dream up a pull request on the project! It hasn't been updated in 3 years...

 

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