What's the difference between a function and a method in Javascript?

Given that Javascript is not the language I program in most of the time, I tend to make the mistake of referring to all functions as methods. There is in fact, a subtle difference.

In Javascript, a method is a function that is assigned to an object.

Here, speak() is a method on the chicken object:

const chicken = {
	name: "Clive",
	speak: () => {
		console.log("BWARK!")
	}
}

chicken.speak()

Written as a function, we would have:

const speak = () => {
	console.log("BWARK!")
}

speak()

It's important to note that when we write a method as an arrow function, it doesn't have access to the other properties on the object. For instance:

const chicken = {
	name: "Clive",
	noise: "BWARK!",
	speak: () => {
		console.log(`${this.noise}`)
	}
}

chicken.speak()

When run, this will return a noise most uncharacteristic of a chicken:

undefined

Written as a traditional function however, we have access to the object using this:

const chicken = {
	name: "Clive",
	noise: "BWARK!",
	speak: function() {
		console.log(`${this.noise}`)
	}
}

chicken.speak()

BWARK!