Immutable DateTime/TimeSpan for TypeScript based on .NET DateTime
#typescript#showdev#javascript
Akash Kava

Akash Kava @akashkava

About: Author of Web Atoms

Location:
India
Joined:
Jan 6, 2018

Immutable DateTime/TimeSpan for TypeScript based on .NET DateTime

Publish Date: Oct 3 '19
10 0

Immutable DateTime

Date object is not immutable, and also modifying it is little complicated. There is no TimeSpan equivalent in JavaScript. So this library was created to provide DateTime/TimeSpan similar to .NET.

I know about moment-js, but I needed something very simpler.

Features

  1. Immutable DateTime
  2. Support for TimeSpan (differences between dates)
  3. Simple Add/Difference
  4. Support for properties (year, month, day, hour, minute, second .. all are readonly properties)
  5. Backward compatibility with JavaScript's Date

Compatibility with Date

In order to make usage simple, you can pass DateTime to any method that uses Date and everything will still work. To prevent intellisense from listing all Date's methods, we have used a hack to create new Date object in constructor of DateTime.

For easy access, all to*String methods of Date are available in intellisense.



   const d = DateTime.now();
   console.log(d instance of Date); // prints true..
   console.log(d instance of DateTime); // prints true..

   // however intellisense does not
   // show up Date methods
   d.year
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This library does not pollute Date's prototype, logically DateTime is a new class and has its own way of functioning.

Json Parser

You will have to hook some code to change prototype of Date objects sent through JSON.parse. d.prototype = DateTime.prototype.

Usage

Properties

Year, Month, Day, Hour, Minute, Second and Millisecond are all properties.




   // now is a readonly property which returns new
   // instance of DateTime of current system time
   const d = DateTime.now;

   console.log(`${d.year}-${d.month}-${d.day}`);
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Trim Time 



   const d = DateTime.now;

   // returns new instance of DateTime
   // with time part trimmed...
   const day = d.date;
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TimeSpan 



   const d = DateTime.now;

   // t is of type TimeSpan
   const t = d.time;

   console.log(t); // prints 10.00 PM (local time)
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Difference in TimeSpan 




   const d1 = new DateTime(2010, 1, 1);
   const d2 = new DateTime(2012, 1, 1);

   // returns TimeSpan
   const diff = d2.diff(d1);

   // prints 730
   console.log(diff.totalDays);
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Add TimeSpan 




   const t = TimeSpan.fromDays(2);
   const d1 = new DateTime(2010, 1, 1);

   const d2 = d1.add(t);

   // prints 2010-01-03
   console.log(d2);
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Type Information 



export default class DateTime {
    static get today(): DateTime;
    static get utcNow(): DateTime;
    static get now(): DateTime;

    static parse(s: string): DateTime;

    get hour(): number;
    get minute(): number;
    get second(): number;
    get millisecond(): number;
    get day(): number;
    get dayOfWeek(): number;
    get month(): number;
    get year(): number;
    get timeZoneOffset(): TimeSpan;
    get msSinceEpoch(): number;

    /** Strips time of the day and returns Date only */
    get date(): DateTime;

    get asJSDate(): Date;

    get time(): TimeSpan;

    constructor();
    constructor(time?: number | string);
    constructor(year?: number, 
       month?: number, date?: number, hours?: number,
       minutes?: number, seconds?: number, ms?: number);

    add(d: DateTime | TimeSpan): DateTime;

    add(days: number, hours?: number, minutes?: number,
       seconds?: number, milliseconds?: number): DateTime;

    addMonths(m: number): DateTime;
    addYears(y: number): DateTime;

    diff(rhs: Date | DateTime): TimeSpan;
    equals(d: DateTime): boolean;

    // for easy access, following methods
    // are available on intellisense

    toLocaleString (locales?: string | string[],
       options?: Intl.DateTimeFormatOptions): string;

    toLocaleDateString (locales?: string | string[],
       options?: Intl.DateTimeFormatOptions): string;

    toLocaleTimeString (locales?: string | string[],
       options?: Intl.DateTimeFormatOptions): string;

    toUTCString(): string;

    toISOString(): string;

    toJSON(key?: any): string;
    toTimeString(): string;
    toDateString(): string;
}
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GitHub logo web-atoms / date-time

DateTime library for Web Atoms

Action Status npm version

@web-atoms/date-time

Immutable DateTime library for Web Atoms in JavaScript similar to .Net DateTime and TimeSpan

Features

  1. Immutable DateTime
  2. Support for TimeSpan (differences between dates)
  3. Simple Add/Difference
  4. Support for properties
  5. Support for Comparison
  6. Support for valueOf which makes it easier to compare and sort dates
  7. Backward compatibility with JavaScript's Date

Compatibility

In order to make usage simple, you can pass DateTime to any method that uses Date and everything will still work. To prevent intellisense from listing all Date's methods, we have used a hack to create new Date object in constructor of DateTime.

For easy access, all to*String methods of Date are available in intellisense.

   const d = DateTime.now();
   console.log(d instance of Date); // prints true..

   // however intellisense does not
   // show up for Date methods except for toLocaleDateString etc
   d.year
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Usage

Properties

Year, Month, Day…


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