Discover the format of irregular date strings needed for parsing.

npm i @fredlackey/ugly-date

This library is an experiment... something I could not shake out of my head one Friday evening. It is not complete. While it does handle basic formats, containing numerics and such, it does not contain logic to handle words or "week of year" / "day of year" logic.

Countless libraries out there that will parse a date string if you supply a string and a format. Most of them will also try to return a valid date if you do not supply a format. In that scenario, the date value often comes back wrong or incomplete. In fact, it is the reason why moment, the de facto library for date manipulation (that i know of), is pulling out their parse logic for scenarios where a format is not supplied.

Simply supply a value to the .analyze function for a report on where recognized patterns are found within the string.

const uglyDate = require('@fredlackey/ugly-date');

const value    = 'Screen Shot 2015-07-09 at 1.33.25 PM';

const results  = uglyDate.analyze(value);

Example results:

{
  "date": "2015-07-09T17:33:25.000Z"
  "hasDate": true,
  "hasDay": false,
  "hasTime": true,
  "pattern": "Screen Shot YYYY-MM-DD at hh.mm.ss a",
  "value": "Screen Shot 2015-07-09 at 1.33.25 PM",
  "values": {
    "YYYY": 2015,
    "MM": 7,
    "DD": 9,
    "h": 1,
    "mm": 33,
    "ss": 25,
    "aa": "PM"
  },
  "locations": [
    {
      "formal": "YYYY-MM-DD",
      "pattern": "YYYY-MM-DD",
      "position": 12,
      "type": "DATE",
      "value": "2015-07-09",
      "values": {
        "YYYY": 2015,
        "MM": 7,
        "DD": 9
      }
    },
    {
      "formal": "hh.mm.ss a",
      "pattern": "h:mm:ss aa",
      "position": 26,
      "type": "TIME",
      "value": "1.33.25 PM",
      "values": {
        "h": 1,
        "mm": 33,
        "ss": 25,
        "aa": "PM"
      }
    }
  ]
}

In the example above, the following values are returned:

• date : Date object, if a full date could be constructed.
• hasDate : Boolean indicating if a valid date value exists.
• hasDay : Boolean indicating if a valid day value exists.
• hasTime : Boolean indicating if a valid time value exists.
• pattern : Example string including the detected pattern.
• value : Original string (for verification puposes).
• values : All detected keys (ie result.values.YYYY).
• locations : Array of locations where patterns were detected.

And, for each location item, you have the following:

• pattern : Actual pattern detected in supplied string.
• position : Index of the substring having the pattern.
• value : Value of the substring matched on the pattern.
• formal : The actual formal / proper pattern to parse this pattern.
• values : Each of the extracted values in their number or string form.

Note:
Pay close attention to the a and aa paterns shown in the formal and pattern values. In this example, he double-character formatted value was detected, however this is not the proper token to use when parsing strings. Intead, the single a is used. While both are provided here, you would want to use the formal value as the actual pattern when parsing this string.

As always, get in touch if you have ideas or feedback ...

Fred Lackey
http://fredlackey.com
[email protected]