GENERATORS

Generators are a delightfully flexible construct introduced in the ECMAScript 6 specification that offers the ability to pause and resume code execution inside a single function block. The implications of this new ability are profound; it allows for, among many other things, the ability to define custom iterators and implement coroutines.

Generator Basics

Generators take the form of a function, and the generator designation is performed with an asterisk. Anywhere a function definition is valid, a generator function definition is also valid:

// Generator function declaration
function* generatorFn() {}

// Generator function expression
let generatorFn = function* () {}

// Object literal method generator function
let foo = {
 * generatorFn() {}
}

// Class instance method generator function
class Foo {
 * generatorFn() {}
}

// Class static method generator function
class Bar {
 static * generatorFn() {}
}

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NOTE   Arrow functions cannot be used as generator...