146 lines
4.6 KiB
Markdown
146 lines
4.6 KiB
Markdown
# Schedule Later
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schedule-later provides methods for managing date-time based tasks, such as starting timeouts and intervals at a specific time of day. Under-the-hood, it uses `setTimeout` and `setInterval`.
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## Install
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```bash
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npm install schedule-later
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```
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or
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```bash
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yarn add schedule-later
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```
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## Import
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```typescript
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import { startTimeout, startInterval, TimeInMS } from 'schedule-later'
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```
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## Key Concepts
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### TimeOfDay
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A `TimeOfDay` object is used to represent a specific time of day. It is an object containing the `hour`, `minute`, and `seconds`.
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```typescript
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export interface TimeOfDay {
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hour: number
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minute?: number
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seconds?: number
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}
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```
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### TimeUntil
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A `TimeUntil` object is used to represent a specific time until a certain event. It can represent time until a certain date, milliseconds from now, or a specific time of day.
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```typescript
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export type TimeUntil = {
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timeOfDay?: TimeOfDay
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date?: Date
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ms?: number
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}
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```
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## Usage
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The `Scheduler` class provides two main static methods: `startTimeout` and `startInterval`.
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### startTimeout
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The `startTimeout` method starts a timeout that calls a given function after a specific delay. The delay is calculated based on the `TimeUntil` object passed to it. The method returns a `StopFunction` (see below).
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```typescript
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function startTimeout(timerFunc: Function, start: TimeUntil): StopFunction
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```
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### startInterval
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The `startInterval` method starts an interval that calls a given function repeatedly with a fixed time delay between each call. Like `startTimeout`, the initial delay is calculated based on a `TimeUntil` object. If called with `callbackAfterTimeout` set to `true`, it will call the callback function after the timeout has finished running (right when starting the interval). The method returns a `StopFunction` (see below).
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```typescript
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function startInterval(
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intervalFunc: Function,
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intervalMS: number,
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start?: TimeUntil
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callbackAfterTimeout: boolean = false
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): StopFunction
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```
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## Stop Functions
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Both the `startTimeout` and `startInterval` methods return a `StopFunction`. This function can be called to cancel a timeout or interval.
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When called with no arguments, the `StopFunction` stops the timeout or interval immediately. If called with a `TimeUntil` argument, it schedules a stop at the specified time.
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Here is the type definition of a `StopFunction`:
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```typescript
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type StopFunction = (stopTime?: TimeUntil) => StopCancelFunction | null
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```
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## Stop Cancel Functions
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The `StopFunction` will return a `StopCancelFunction` when called with a stopTime. This function can be called to cancel a scheduled stop.
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```typescript
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type StopCancelFunction = (stopRunning: boolean = false) => void
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```
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In the `StopCancelFunction`, if the `stopRunning` parameter is `true`, it stops the timeout or interval immediately. If `stopRunning` is `false`, it cancels the scheduled stop.
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## Examples
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1. Start a timeout that says "Hello, world!" after 10 seconds, then stop it after 5 seconds.
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```typescript
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const sayHello = () => console.log('Hello, world!')
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// Start a timeout that says "Hello, world!" after 10 seconds, and stop it after 5 seconds.
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let stopTimeout = Scheduler.startTimeout(sayHello, { ms: 10000 })
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stopTimeout({ ms: 5000 })
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```
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2. Using startTimeout with a specific time of day
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```typescript
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const goodMorning = () => console.log('Good morning!')
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let stopTimeout = Scheduler.startTimeout(goodMorning, {
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timeOfDay: { hour: 7, minute: 0 },
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})
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// Later, if you want to cancel the morning greeting
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stopTimeout()
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```
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In this example, the goodMorning function will be called at 7:00 AM. If you want to cancel the morning greeting (for example, the user chose to sleep in), you can call the stopTimeout function.
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3. Using startInterval with a specific interval, basically a regular setInterval. Uses the TimeInMS enum to clearly specify the interval.
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```typescript
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const sayHello = () => console.log('Hello, world!')
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let stopInterval = Scheduler.startInterval(sayHello, TimeInMS.SECOND * 5)
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// Later, if you want to stop the interval
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stopInterval()
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```
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4. Using startInterval with a specific time of day
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```typescript
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const sayHello = () => console.log('Hello, world!')
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let stopInterval = Scheduler.startInterval(sayHello, 1000, {
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timeOfDay: { hour: 7, minute: 0 },
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})
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// Later, if you want to stop the interval
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stopInterval()
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```
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In this example, the sayHello function will be called every 1000 milliseconds starting at 7:00 AM. If you want to cancel the morning greeting (for example, the user chose to sleep in), you can call the stopInterval function.
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