JavaScript: How to Extract the Date from ISO 8601 Complete Date and Time Format (Plus Make It Readable)

The complete format looks like this:
YYYY-MM-DDThh:mm:ss.sTZD

Example:
1997-07-16T19:20:30.45+01:00

www.w3.org/TR/NOTE-datetime

We want to extract everything before the letter "T" ("Time") there, the date pattern. And make the month as strings, e.g. March, May, July, and so forth. Plus, re-format the structure.

This is in JavaScript. For other programming languages, there are built-in features to do it, perhaps.
Like in Python, whoa dude.

First, split the string

Let's take the 1997-07-16T19:20:30.45+01:00 as an example input string.

var input = "1997-07-16T19:20:30.45+01:00"; //string.
input = input.split("T"); //array.
//the "input" variable is now an array: ["1997-07-16", "19:20:30.45+01:00"]

Second, get the first array element and split it again

//the "input" is already an array from above method.
//take only the first element. Redefine the "input".
input = input[0]; //string: "1997-07-16"
input = input.split("-"); //array
//the "input" variable is now an array: ["1997", "07", "16"]

Third, define month names, day, month, and year variables

//the "input" is now an array: ["1997", "07", "16"]
var monthNames, day, month, year;
monthNames = "January,February,March,April,May,June,July,August,September,October,November,December"; //string
monthNames = monthNames.split(","); //to array
day = input[2]; //the last array element (index: 2) is the day
month = input[1]; //the middle is the month
year = input[0]; //the year is the first element

Fourth, convert the month number into string

month = monthNames[Number(month) - 1];

//The - 1 (minus one) above is because the array index starts from 0, not 1.
//The 1st month from the date pattern has 1 as the month number, not 0.
//Thus the "minus one".

The last, let's combine them all into one function block

function extractDate(a) {
    "use strict";
    var input, monthNames, day, month, year;    
    //we can chain the methods for "input" variable:
    input = a.split("T")[0].split("-");
    day = input[2];
    month = input[1];
    year = input[0];
    monthNames = "January,February,March,April,May,June,July,August,September,October,November,December";
    monthNames = monthNames.split(",");
    return monthNames[Number(month) - 1] + " " + day + ", " + year;
}

Usage

extractDate("1997-07-16T19:20:30.45+01:00");
//the output will be: "July 16, 1997"

This is only for the date

If your thingy there needs to show every single of them, then build another methods/functions to process the time (hour:minute:second.millisecond am/pm) and the time zone (TZD).

For example

See the Pen DateTime ISO-8601 Extractor by Monkey Raptor (@monkeyraptor) on CodePen.

A tool to find out the weekday name of a particular date, on Port Raptor

Monkey Raptor

Monkey Raptor

Wednesday, September 30, 2015

JavaScript: How to Extract the Date from ISO 8601 Complete Date and Time Format (Plus Make It Readable)

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