JavaScriptの関数の中から見えるthisはすげ替えも可能なのわね。ぐえぇ。
https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_objects/Function/bind
ActionCableの例で関数プロパティ中で別の関数プッロパティのthisを挿げ替えてるっぽくてどゆことなん
initialized() {
this.update = this.update.bind(this)
},
update() {
this.documentIsActive ? this.appear() : this.away()
},
あー。このupdate()はコールバックとして呼ばれるからbing()しておかないとthisがコールバック元のコンテキストになっちゃうのかな？
developer.mozilla.orgFunction.prototype.bind() - JavaScript | MDNThe bind() method creates a new
function that, when called, has its this keyword set to the provided
value, with a given sequence of arguments preceding any provided when the new function
is called.
guides.rubyonrails.orgAction Cable Overview — Ruby on Rails GuidesAction Cable OverviewIn this guide, you will learn how Action Cable works and how to use WebSockets to incorporate real-time features into your Rails application.After reading this guide, you will know: What Action Cable is and its integration backend and frontend How to set up Action Cable How to set up channels Deployment and Architecture setup for running Action Cable