How do I express dates in TypeScript? Dates aren't a TypeScript type, so do I use any or object? Seems like there would be a "right" way to do:
let myDate: any = new Date(); I couldn't find much on Google, despite it being such a simple question.
The answer is super simple, the type is Date:
const d: Date = new Date(); // but the type can also be inferred from "new Date()" already It is the same as with every other object instance :)
Any class or interface can be used as a type in TypeScript.
const date = new Date(); will already know about the date type definition as Date is an internal TypeScript object referenced by the DateConstructor interface.
And for the constructor you used, it is defined as:
interface DateConstructor { new(): Date; ... } To make it more explicit, you can use:
const date: Date = new Date(); You might be missing the type definitions though, the Date is comming for my example from the ES6 lib, and in my tsconfig.json I have defined:
"compilerOptions": { "target": "ES6", "lib": [ "es6", "dom" ], You might adapt these settings to target your wanted version of JavaScript.
The Date is by the way an Interface from lib.es6.d.ts:
/** Enables basic storage and retrieval of dates and times. */ interface Date { /** Returns a string representation of a date. The format of the string depends on the locale. */ toString(): string; /** Returns a date as a string value. */ toDateString(): string; /** Returns a time as a string value. */ toTimeString(): string; /** Returns a value as a string value appropriate to the host environment's current locale. */ toLocaleString(): string; /** Returns a date as a string value appropriate to the host environment's current locale. */ toLocaleDateString(): string; /** Returns a time as a string value appropriate to the host environment's current locale. */ toLocaleTimeString(): string; /** Returns the stored time value in milliseconds since midnight, January 1, 1970 UTC. */ valueOf(): number; /** Gets the time value in milliseconds. */ getTime(): number; /** Gets the year, using local time. */ getFullYear(): number; /** Gets the year using Universal Coordinated Time (UTC). */ getUTCFullYear(): number; /** Gets the month, using local time. */ getMonth(): number; /** Gets the month of a Date object using Universal Coordinated Time (UTC). */ getUTCMonth(): number; /** Gets the day-of-the-month, using local time. */ getDate(): number; /** Gets the day-of-the-month, using Universal Coordinated Time (UTC). */ getUTCDate(): number; /** Gets the day of the week, using local time. */ getDay(): number; /** Gets the day of the week using Universal Coordinated Time (UTC). */ getUTCDay(): number; /** Gets the hours in a date, using local time. */ getHours(): number; /** Gets the hours value in a Date object using Universal Coordinated Time (UTC). */ getUTCHours(): number; /** Gets the minutes of a Date object, using local time. */ getMinutes(): number; /** Gets the minutes of a Date object using Universal Coordinated Time (UTC). */ getUTCMinutes(): number; /** Gets the seconds of a Date object, using local time. */ getSeconds(): number; /** Gets the seconds of a Date object using Universal Coordinated Time (UTC). */ getUTCSeconds(): number; /** Gets the milliseconds of a Date, using local time. */ getMilliseconds(): number; /** Gets the milliseconds of a Date object using Universal Coordinated Time (UTC). */ getUTCMilliseconds(): number; /** Gets the difference in minutes between the time on the local computer and Universal Coordinated Time (UTC). */ getTimezoneOffset(): number; /** * Sets the date and time value in the Date object. * @param time A numeric value representing the number of elapsed milliseconds since midnight, January 1, 1970 GMT. */ setTime(time: number): number; /** * Sets the milliseconds value in the Date object using local time. * @param ms A numeric value equal to the millisecond value. */ setMilliseconds(ms: number): number; /** * Sets the milliseconds value in the Date object using Universal Coordinated Time (UTC). * @param ms A numeric value equal to the millisecond value. */ setUTCMilliseconds(ms: number): number; /** * Sets the seconds value in the Date object using local time. * @param sec A numeric value equal to the seconds value. * @param ms A numeric value equal to the milliseconds value. */ setSeconds(sec: number, ms?: number): number; /** * Sets the seconds value in the Date object using Universal Coordinated Time (UTC). * @param sec A numeric value equal to the seconds value. * @param ms A numeric value equal to the milliseconds value. */ setUTCSeconds(sec: number, ms?: number): number; /** * Sets the minutes value in the Date object using local time. * @param min A numeric value equal to the minutes value. * @param sec A numeric value equal to the seconds value. * @param ms A numeric value equal to the milliseconds value. */ setMinutes(min: number, sec?: number, ms?: number): number; /** * Sets the minutes value in the Date object using Universal Coordinated Time (UTC). * @param min A numeric value equal to the minutes value. * @param sec A numeric value equal to the seconds value. * @param ms A numeric value equal to the milliseconds value. */ setUTCMinutes(min: number, sec?: number, ms?: number): number; /** * Sets the hour value in the Date object using local time. * @param hours A numeric value equal to the hours value. * @param min A numeric value equal to the minutes value. * @param sec A numeric value equal to the seconds value. * @param ms A numeric value equal to the milliseconds value. */ setHours(hours: number, min?: number, sec?: number, ms?: number): number; /** * Sets the hours value in the Date object using Universal Coordinated Time (UTC). * @param hours A numeric value equal to the hours value. * @param min A numeric value equal to the minutes value. * @param sec A numeric value equal to the seconds value. * @param ms A numeric value equal to the milliseconds value. */ setUTCHours(hours: number, min?: number, sec?: number, ms?: number): number; /** * Sets the numeric day-of-the-month value of the Date object using local time. * @param date A numeric value equal to the day of the month. */ setDate(date: number): number; /** * Sets the numeric day of the month in the Date object using Universal Coordinated Time (UTC). * @param date A numeric value equal to the day of the month. */ setUTCDate(date: number): number; /** * Sets the month value in the Date object using local time. * @param month A numeric value equal to the month. The value for January is 0, and other month values follow consecutively. * @param date A numeric value representing the day of the month. If this value is not supplied, the value from a call to the getDate method is used. */ setMonth(month: number, date?: number): number; /** * Sets the month value in the Date object using Universal Coordinated Time (UTC). * @param month A numeric value equal to the month. The value for January is 0, and other month values follow consecutively. * @param date A numeric value representing the day of the month. If it is not supplied, the value from a call to the getUTCDate method is used. */ setUTCMonth(month: number, date?: number): number; /** * Sets the year of the Date object using local time. * @param year A numeric value for the year. * @param month A zero-based numeric value for the month (0 for January, 11 for December). Must be specified if numDate is specified. * @param date A numeric value equal for the day of the month. */ setFullYear(year: number, month?: number, date?: number): number; /** * Sets the year value in the Date object using Universal Coordinated Time (UTC). * @param year A numeric value equal to the year. * @param month A numeric value equal to the month. The value for January is 0, and other month values follow consecutively. Must be supplied if numDate is supplied. * @param date A numeric value equal to the day of the month. */ setUTCFullYear(year: number, month?: number, date?: number): number; /** Returns a date converted to a string using Universal Coordinated Time (UTC). */ toUTCString(): string; /** Returns a date as a string value in ISO format. */ toISOString(): string; /** Used by the JSON.stringify method to enable the transformation of an object's data for JavaScript Object Notation (JSON) serialization. */ toJSON(key?: any): string; }