dot-event

dot-event

Javascript event emitter, foundation of everything.

Purpose

Dot-event provides a succinct interface for calling events and persisting state with a tiny footprint (<1kb).

Setup

const dot = require("dot-event")()

Basics

dot.on(() => {}) // listener
dot() // emitter

Return value

dot.on(() => "a")
dot() // "a"

Async return value

dot.on(async () => "a")
dot().then(result => /* [ "a" ] */)

Event id

dot.on("a", () => "b")
dot("a") // "b"

Event id tip: The first string or element in an array of strings passed to dot.on or dot.any is considered the event id.

Event id & props

dot.on("a", "b", "c", prop => prop)
dot("a", "b", "c") // ["b", "c"]

Prop tip 1: Any string or array of strings passed to dot after the event id are considered prop identifiers.

Prop tip 2: The listener function always receives a prop array as its first argument.

Emit argument

dot.on((prop, arg) => arg)
dot({ a: "b" }) // { a: "b" }

Arg tip 1: The last non-prop emit argument is considered the user-provided argument.

Arg tip 2: The listener function always receives the user-provided argument as its second argument.

Any

dot.any(() => "!!!")
dot("a", "b", "c") // "!!!"

Helper function

dot.any("a", props => props)
dot.a("b", "c") // [ "b", "c" ]

Helper tip: Dot-event creates a helper function only if dot.any receives an event id with no props.

Listener arguments

No matter what is passed to the dot emitter, listener functions always receive five arguments:

• prop — an array of string identifiers
• arg — a user-provided argument
• dot — the dot-event instance
• event — the event id
• signal — dot-event signal object (use signal.cancel = true for event cancellation)

Dot composers

Library	Description	URL
ad	Google Publisher Tag functions	https://github.com/dot-event/ad
arg	CLI and URL argument handling	https://github.com/dot-event/arg
fetch	Universal HTTP fetch function	https://github.com/dot-event/fetch
log	Log functions	https://github.com/dot-event/log2
store	Immutable store	https://github.com/dot-event/store2