After a new wave of discussion about CustomEvent vs Event subclasses, I wrote a new blog post on the topic:
TL;DR: Subclass Event instead of using CustomEvent 😎
justinfagnani.com/2025/06/25/s...
TL;DR: Subclass Event instead of using CustomEvent 😎
justinfagnani.com/2025/06/25/s...
Stop Using CustomEvent
justinfagnani.com
June 25, 2025 at 2:56 PM
After a new wave of discussion about CustomEvent vs Event subclasses, I wrote a new blog post on the topic:
TL;DR: Subclass Event instead of using CustomEvent 😎
justinfagnani.com/2025/06/25/s...
TL;DR: Subclass Event instead of using CustomEvent 😎
justinfagnani.com/2025/06/25/s...
Said it before, will say it again:
CustomEvent is *criminally* under-utilized
developer.mozilla.org/en-US/docs/W...
CustomEvent is *criminally* under-utilized
developer.mozilla.org/en-US/docs/W...
CustomEvent: CustomEvent() constructor - Web APIs | MDN
The CustomEvent() constructor creates a new CustomEvent object.
developer.mozilla.org
April 8, 2025 at 4:42 PM
Said it before, will say it again:
CustomEvent is *criminally* under-utilized
developer.mozilla.org/en-US/docs/W...
CustomEvent is *criminally* under-utilized
developer.mozilla.org/en-US/docs/W...
Personally I’d recommend subclassing Event (or CustomEvent) instead of just defining a type!
June 19, 2025 at 1:22 PM
Personally I’d recommend subclassing Event (or CustomEvent) instead of just defining a type!
Events generally (and not CustomEvent, extend Event if needed), or the event-based Context Protocol: github.com/webcomponent...
November 15, 2024 at 6:29 PM
Events generally (and not CustomEvent, extend Event if needed), or the event-based Context Protocol: github.com/webcomponent...
JavaScript Tip 💡
Use 𝙲𝚞𝚜𝚝𝚘𝚖𝙴𝚟𝚎𝚗𝚝 for custom event dispatching and handling in the DOM.
Use 𝙲𝚞𝚜𝚝𝚘𝚖𝙴𝚟𝚎𝚗𝚝 for custom event dispatching and handling in the DOM.
February 1, 2025 at 4:00 PM
JavaScript Tip 💡
Use 𝙲𝚞𝚜𝚝𝚘𝚖𝙴𝚟𝚎𝚗𝚝 for custom event dispatching and handling in the DOM.
Use 𝙲𝚞𝚜𝚝𝚘𝚖𝙴𝚟𝚎𝚗𝚝 for custom event dispatching and handling in the DOM.
Another Q for the web component community--what are the best practices for emitting events? I see a split between preferring prefixing custom events or just emitting regular events.
Shoelace prefers custom events: CustomEvent('sl-open')
Other libs typically emits normal evs: Event('open')
Shoelace prefers custom events: CustomEvent('sl-open')
Other libs typically emits normal evs: Event('open')
March 10, 2025 at 4:36 PM
Another Q for the web component community--what are the best practices for emitting events? I see a split between preferring prefixing custom events or just emitting regular events.
Shoelace prefers custom events: CustomEvent('sl-open')
Other libs typically emits normal evs: Event('open')
Shoelace prefers custom events: CustomEvent('sl-open')
Other libs typically emits normal evs: Event('open')
During the weekend, Skader's had a rad time celebrating Pride this weekend during our #pride #event
#Pride365 #MoreThanAGame #LGBT #LGBTQIA+ #Autism #AutismCommunity #AutismServer #mc #minecraft #minecraftEvent #minecraftResourcePack #CustomEvent #showcase
www.youtube.com/shorts/cZBkq...
#Pride365 #MoreThanAGame #LGBT #LGBTQIA+ #Autism #AutismCommunity #AutismServer #mc #minecraft #minecraftEvent #minecraftResourcePack #CustomEvent #showcase
www.youtube.com/shorts/cZBkq...
Last weekend Skader's had a rad time celebrating #Pride! #pride2025 #pridemonth #pridegaming #shorts
YouTube video by Skade Gaming
www.youtube.com
June 11, 2025 at 5:07 PM
During the weekend, Skader's had a rad time celebrating Pride this weekend during our #pride #event
#Pride365 #MoreThanAGame #LGBT #LGBTQIA+ #Autism #AutismCommunity #AutismServer #mc #minecraft #minecraftEvent #minecraftResourcePack #CustomEvent #showcase
www.youtube.com/shorts/cZBkq...
#Pride365 #MoreThanAGame #LGBT #LGBTQIA+ #Autism #AutismCommunity #AutismServer #mc #minecraft #minecraftEvent #minecraftResourcePack #CustomEvent #showcase
www.youtube.com/shorts/cZBkq...
Guys its ready! the pride Capture The Flag event is now open on @skadegaming.com! Skader's can explore the lobby before the event and check out the cool features dotted around!
#Pride #Minecraft #MinecraftEvent #mc #CaptureTheFlag #PrideCaptureTheFlag #CustomEvent
#Pride #Minecraft #MinecraftEvent #mc #CaptureTheFlag #PrideCaptureTheFlag #CustomEvent
June 27, 2025 at 5:34 PM
Guys its ready! the pride Capture The Flag event is now open on @skadegaming.com! Skader's can explore the lobby before the event and check out the cool features dotted around!
#Pride #Minecraft #MinecraftEvent #mc #CaptureTheFlag #PrideCaptureTheFlag #CustomEvent
#Pride #Minecraft #MinecraftEvent #mc #CaptureTheFlag #PrideCaptureTheFlag #CustomEvent
🚀 Calling all Developers! 💻 Ready to test your coding skills?
What is the correct way to emit an event from a child component in Vue 3 Composition API?
A) emitEvent('customEvent')
B) this.emit('customEvent')
C) emit('customEvent')
D) trigger('customEvent')
#TechQuiz #AI #Developer #VueJS
What is the correct way to emit an event from a child component in Vue 3 Composition API?
A) emitEvent('customEvent')
B) this.emit('customEvent')
C) emit('customEvent')
D) trigger('customEvent')
#TechQuiz #AI #Developer #VueJS
July 9, 2025 at 4:19 PM
🚀 Calling all Developers! 💻 Ready to test your coding skills?
What is the correct way to emit an event from a child component in Vue 3 Composition API?
A) emitEvent('customEvent')
B) this.emit('customEvent')
C) emit('customEvent')
D) trigger('customEvent')
#TechQuiz #AI #Developer #VueJS
What is the correct way to emit an event from a child component in Vue 3 Composition API?
A) emitEvent('customEvent')
B) this.emit('customEvent')
C) emit('customEvent')
D) trigger('customEvent')
#TechQuiz #AI #Developer #VueJS
One advice: don't use CustomEvent. Instead, extend the Event class and implement your custom logic there. CustomEvent is some backport hackery that was never meant to be used.
November 13, 2025 at 7:49 PM
One advice: don't use CustomEvent. Instead, extend the Event class and implement your custom logic there. CustomEvent is some backport hackery that was never meant to be used.
Stop using CustomEvent in JavaScript.
There is a much better way to handle custom events.
#JavaScript #TypeScript #WebDev
1/5
There is a much better way to handle custom events.
#JavaScript #TypeScript #WebDev
1/5
September 10, 2026 at 8:02 PM
Stop using CustomEvent in JavaScript.
There is a much better way to handle custom events.
#JavaScript #TypeScript #WebDev
1/5
There is a much better way to handle custom events.
#JavaScript #TypeScript #WebDev
1/5
I'm not sure what the value-add is here for a component that side-steps both Event and CustomEvent, repeats the mistakes of CustomEvent, and doesn't do what the comment says it does (since bubble and compose are not provided as defaults).
github.com/umbraco/Umbr...
github.com/umbraco/Umbr...
github.com
January 27, 2025 at 5:33 PM
I'm not sure what the value-add is here for a component that side-steps both Event and CustomEvent, repeats the mistakes of CustomEvent, and doesn't do what the comment says it does (since bubble and compose are not provided as defaults).
github.com/umbraco/Umbr...
github.com/umbraco/Umbr...
cara, a maior parte da minha engine é esse código aqui:
const click = () => {
if (editor) {
const script = base + editor.getValue() + fim
const saida = eval(script) // <<=======
window.dispatchEvent(new CustomEvent("movimentos", { detail : {movimentos: saida }, bubbles: true}))
}
}
const click = () => {
if (editor) {
const script = base + editor.getValue() + fim
const saida = eval(script) // <<=======
window.dispatchEvent(new CustomEvent("movimentos", { detail : {movimentos: saida }, bubbles: true}))
}
}
September 26, 2024 at 11:44 AM
cara, a maior parte da minha engine é esse código aqui:
const click = () => {
if (editor) {
const script = base + editor.getValue() + fim
const saida = eval(script) // <<=======
window.dispatchEvent(new CustomEvent("movimentos", { detail : {movimentos: saida }, bubbles: true}))
}
}
const click = () => {
if (editor) {
const script = base + editor.getValue() + fim
const saida = eval(script) // <<=======
window.dispatchEvent(new CustomEvent("movimentos", { detail : {movimentos: saida }, bubbles: true}))
}
}
I'm liking that more too, but decided to show the typed version first for 2 reasons:
1. I think CustomEvent tends to be the most common and is still a viable option
2. Teams may want to switch to subclassing, but may not be in a position to introduce breaking changes, but can update the types
1. I think CustomEvent tends to be the most common and is still a viable option
2. Teams may want to switch to subclassing, but may not be in a position to introduce breaking changes, but can update the types
June 19, 2025 at 2:39 PM
I'm liking that more too, but decided to show the typed version first for 2 reasons:
1. I think CustomEvent tends to be the most common and is still a viable option
2. Teams may want to switch to subclassing, but may not be in a position to introduce breaking changes, but can update the types
1. I think CustomEvent tends to be the most common and is still a viable option
2. Teams may want to switch to subclassing, but may not be in a position to introduce breaking changes, but can update the types
CustomEvent投げるの面白い "react-spectrum/packages/@react-spectrum/toast/src/ToastContainer.tsx at main · adobe/react-spectrum" https://github.com/adobe/react-spectrum/blob/main/packages/%40react-spectrum/toast/src/ToastContainer.tsx
May 26, 2024 at 1:30 AM
CustomEvent投げるの面白い "react-spectrum/packages/@react-spectrum/toast/src/ToastContainer.tsx at main · adobe/react-spectrum" https://github.com/adobe/react-spectrum/blob/main/packages/%40react-spectrum/toast/src/ToastContainer.tsx
🛠️ How to Create Custom Events in Business Central AL Code {Part 1} youtu.be/Riay2MqIwCA?... via @YouTube
#Msdyn365bc #CustomEvent #BCALHelp #ALHelp #BusinessCentral #IntegrationEvent #BusinessEvent #ALCode #IsHandled
#Msdyn365bc #CustomEvent #BCALHelp #ALHelp #BusinessCentral #IntegrationEvent #BusinessEvent #ALCode #IsHandled
🛠️ How to Create Custom Events in Business Central AL Code {Part 1}
YouTube video by saurav dhyani
youtu.be
February 26, 2025 at 8:10 AM
🛠️ How to Create Custom Events in Business Central AL Code {Part 1} youtu.be/Riay2MqIwCA?... via @YouTube
#Msdyn365bc #CustomEvent #BCALHelp #ALHelp #BusinessCentral #IntegrationEvent #BusinessEvent #ALCode #IsHandled
#Msdyn365bc #CustomEvent #BCALHelp #ALHelp #BusinessCentral #IntegrationEvent #BusinessEvent #ALCode #IsHandled
Remix 3でpropsが変わった(=親がupdateした)時の処理が書きにくい問題について考えた結果、原因は親が子を自動的に再レンダリングするせいでは？と思った
なので再レンダリングの代わりに親がupdateしたことを伝えるCustomEventをdispatchするようにしたらいいのではないかと思った
具体的にはこんな感じ
メリットとして全ての処理が1つのイベントの中に集約され、不要な再レンダリングが起きないようになる
なので再レンダリングの代わりに親がupdateしたことを伝えるCustomEventをdispatchするようにしたらいいのではないかと思った
具体的にはこんな感じ
メリットとして全ての処理が1つのイベントの中に集約され、不要な再レンダリングが起きないようになる
October 14, 2025 at 10:14 AM
Remix 3でpropsが変わった(=親がupdateした)時の処理が書きにくい問題について考えた結果、原因は親が子を自動的に再レンダリングするせいでは？と思った
なので再レンダリングの代わりに親がupdateしたことを伝えるCustomEventをdispatchするようにしたらいいのではないかと思った
具体的にはこんな感じ
メリットとして全ての処理が1つのイベントの中に集約され、不要な再レンダリングが起きないようになる
なので再レンダリングの代わりに親がupdateしたことを伝えるCustomEventをdispatchするようにしたらいいのではないかと思った
具体的にはこんな感じ
メリットとして全ての処理が1つのイベントの中に集約され、不要な再レンダリングが起きないようになる
1. The problem with CustomEvent.
For years, developers used CustomEvent to pass data.
You must always wrap your data inside a detail property.
You cannot access your values directly.
It is also hard to type properly in TypeScript.
2/5
For years, developers used CustomEvent to pass data.
You must always wrap your data inside a detail property.
You cannot access your values directly.
It is also hard to type properly in TypeScript.
2/5
September 10, 2026 at 8:02 PM
1. The problem with CustomEvent.
For years, developers used CustomEvent to pass data.
You must always wrap your data inside a detail property.
You cannot access your values directly.
It is also hard to type properly in TypeScript.
2/5
For years, developers used CustomEvent to pass data.
You must always wrap your data inside a detail property.
You cannot access your values directly.
It is also hard to type properly in TypeScript.
2/5
Extending Event makes your code cleaner.
It makes your codebase easier to maintain.
Do you still use CustomEvent?
Or have you already switched to extending Event?
5/5
It makes your codebase easier to maintain.
Do you still use CustomEvent?
Or have you already switched to extending Event?
5/5
September 10, 2026 at 8:02 PM
Extending Event makes your code cleaner.
It makes your codebase easier to maintain.
Do you still use CustomEvent?
Or have you already switched to extending Event?
5/5
It makes your codebase easier to maintain.
Do you still use CustomEvent?
Or have you already switched to extending Event?
5/5
Custom Events are so underused. I love them.
developer.mozilla.org/en-US/docs/W...
developer.mozilla.org/en-US/docs/W...
CustomEvent: CustomEvent() constructor - Web APIs | MDN
The CustomEvent() constructor creates a new CustomEvent object.
developer.mozilla.org
March 4, 2025 at 10:51 AM
Custom Events are so underused. I love them.
developer.mozilla.org/en-US/docs/W...
developer.mozilla.org/en-US/docs/W...
あれ引数付きCustomEventってLive入ったんだっけ
July 2, 2025 at 7:58 AM
あれ引数付きCustomEventってLive入ったんだっけ
VRCで使えるすごいライトが増え
CustomEventで引数が使えるようになり
CyanTriggerが壊れた
CustomEventで引数が使えるようになり
CyanTriggerが壊れた
May 24, 2025 at 12:07 PM
VRCで使えるすごいライトが増え
CustomEventで引数が使えるようになり
CyanTriggerが壊れた
CustomEventで引数が使えるようになり
CyanTriggerが壊れた
Udonに引数付きCustomEventが来るらしい、期待
April 24, 2025 at 10:58 PM
Udonに引数付きCustomEventが来るらしい、期待
CustomEvent系、あくまでもその場にいる人に何かしら発火させるためのそれだから、late-joiner対応は別途状態保持用の変数と状態同期用のメソッドが必要がち
January 15, 2025 at 9:07 AM
CustomEvent系、あくまでもその場にいる人に何かしら発火させるためのそれだから、late-joiner対応は別途状態保持用の変数と状態同期用のメソッドが必要がち
Merged PR into main at bluesky-social/atproto: Provide a ponyfill for CustomEvent (#2710)
August 15, 2024 at 4:48 PM
Merged PR into main at bluesky-social/atproto: Provide a ponyfill for CustomEvent (#2710)