tags: #js #javascript #class #method #public #field #function

## Public Class Field Functions instead of Class Methods
See [this at mozilla](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Classes/Public_class_fields) and [can I use](https://caniuse.com/?search=class%20fields) for compatibility information.

If you have e.g.
```javascript
class A {
  constructor() {
    window.addEventListener("resize",this.resize)
  }
  resize() {
    console.log(this)
  }
}
```
then `resize()` would show that `this === window`, not the `A` instance. 
In earlier versions of Javascript, you had to put this in your constructor:
```
  constructor() {
    window.addEventListener("resize",this.resize)
    this.resize = this.resize.bind(this)
  }
```
and doing this for every method gets annoying quickly. In newer versions
of Javascript, you can instead just do
```
  resize = () => {
    ..
  }
```
and when resize is invoked, it will capture the value of `this` from when the constructor was running, which
is what we generally want.