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Generator functions.To create a generator, we need a special syntax construct: function*, so-called “… generator function”.… Generators may generate values forever In the examples above we generated finite sequences… syntax to generate values.… Generators are created by generator functions function* f(…) {…}.

Generators are labelled with function* (note the star) and use yield to generate a value, then we can… generates a sequence of values, we can use an asynchronous generator.… It’s generated by GitHub itself.… Summary.Regular iterators and generators work fine with the data that doesn’t take time to generate.… : Generators Async generators Declaration function* async function* next() return value is

We can not only assign handlers, but also generate events from JavaScript.… We can generate not only completely new events, that we invent for our own purposes, but also built-in… Browser-generated events always have the right type.… Summary.To generate an event from code, we first need to create an event object.… We shouldn’t generate browser events as it’s a hacky way to run handlers.

Or we have a class User and a class EventEmitter that implements event generation, and we’d like to add… An important feature of many browser objects (for instance) is that they can generate events.… Or, a menu can generate the event "select" when a menu item is selected, and other objects… Summary.Mixin – is a generic object-oriented programming term: a class that contains methods for other… So generally one should think well about the naming methods of a mixin, to minimize the probability of

And JavaScript generally has no concept of “aborting” a promise.… Generally, we have two parties in the process: The one that performs a cancelable operation, it sets… AbortController is a simple object that generates an abort event on its signal property when the abort

Further inheritance.The ValidationError class is very generic. Many things may go wrong.… The human-readable message is generated by the constructor.… have SyntaxError and ValidationError, but in the future readUser function may grow and probably generate… If the readUser function generates several kinds of errors, then we should ask ourselves: do we really… We’ll make a new class ReadError to represent a generic “data reading” error.

The brief history.Let’s make a small overview, so that you understand the general picture and the place… For the existing scripts to work, they generated (and still generate) mouse events.… For instance, tapping a touchscreen generates mousedown.… Browser-generated.… native drag’n’drop support for images, that kicks in and takes over the drag’n’drop process, thus generating

But generally we should try to keep the code simple and self-descriptive.… Also, there are tools like JSDoc 3 that can generate HTML-documentation from the comments.… Comments are also used for auto-documenting tools like JSDoc3: they read them and generate HTML-docs

If json is malformed, JSON.parse generates an error, so the script “dies”.… “Throw” operator.The throw operator generates an error.… Let’s see what kind of error JSON.parse generates… a SyntaxError with the given message, the same way as JavaScript would generate it itself.… We can also generate our own errors using the throw operator.

All DOM nodes generate such signals (but events are not limited to DOM).… take a look at: Mouse events: click – when the mouse clicks on an element (touchscreen devices generate… So the markup generates this property:… But generally we use only one of these ways.… We’ll learn more about events in general and about different types of events in the next chapters.

Where’s the code that generates… But that is generally a bad idea.… So, generally, modifying a native prototype is considered a bad idea.

Rabbit class should be based on Animal, have access to animal methods, so that rabbits can do what “generic… That’s why dates have access to generic object methods.… That may be useful for advanced programming patterns when we use functions to generate classes depending… a class extends another class and has no constructor, then the following “empty” constructor is generated… Methods are not “free”.As we’ve known before, generally functions are “free”, not bound to objects in

Focusing on an element generally means: “prepare to accept the data here”, so that’s the moment when… Losing the focus generally means: “the data has been entered”, so we can run the code to check it or… In practice though, one should think well, before implementing something like this, because we generally

Iterable objects are a generalization of arrays.… object, a so-called “iterator” is created by the call to range[Symbol.iterator](), and its next() generates… Or we can make an iterable object that generates an infinite sequence of pseudorandom numbers.

That’s allowed for historical reasons, and mostly works, but generally… not recommended, because: If the key is user-generated, it can be anything, like length or toString… Triggers on all window objects that have access to the storage except the one that generated it (within

Then the submit event is not generated.

First, we can’t dynamically generate any parameters of import.

Some of the optimizations: Generational collection – objects are split into two sets: “new ones” and… A general book “The Garbage Collection Handbook: The Art of Automatic Memory Management” (R.… Naturally, to learn more about garbage collection, you’d better prepare by learning about V8 internals in general

By clicking on a link you download a dynamically-generated Blob with hello world contents as a file:… link.href looks like: For each URL generated… A generated URL (and hence the link with it) is only valid within the current document, while it’s open

see below), base – an optional base URL: if set and url argument has only path, then the URL is generated… Generally, the URL object can be passed to any method instead of a string, as most methods will perform

If we don’t have try..catch, then the promise generated… promise makes JavaScript wait until that promise settles, and then: If it’s an error, an exception is generated

All forms generated by bank.com have a special field, a so-called “XSRF protection token”, that an evil… page can’t generate or extract from a remote page.… We could work around that by using two cookies: one for “general recognition”, only to say: “Hello, John… given name: Here new RegExp is generated… Websites generally have two variants of complying with GDPR.

simple, slightly modified variants of that code have practical uses, for instance, as a random number generator… to generate random values for automated tests.… Closure There is a general programming term “closure”, that developers generally should know

These methods are generic, there is a common agreement to use them for data structures.

That said, using global variables is generally

For each such message, the message event is generated:… Event types.By default EventSource object generates three events: message – a message received, available

That’s all right, as our task is usually to perform “general” finalizing procedures.… As said, it’s a place to do generic cleanup, no matter what the outcome was.… helpful and make things work just the right way if we use finally how it’s supposed to be used: for generic

Or we can auto-generate keys. But we need to create an object store first.… will use as the key, e.g. id. autoIncrement – if true, then the key for a newly stored object is generated… the same key, then the request fails, and an error with the name "ConstraintError" is generated… The store.add method generates a "ConstraintError" in that case.… The index will enforce that by generating an error if we try to add a duplicate. multiEntry – only used

There are generally two ways to style an element: Create a class in CSS and add it: <div class="… Nothing, or maybe a “generated” value from known paddings?

Touch devices also generate similar events when one taps on them.… The problem is: a left-click with Ctrl is interpreted as a right-click on MacOS, and it generates the

As of now, we’ve got to know about use strict in general.

So, if we’re talking about a very small service, the approach may be viable, but generally, it needs

But now we understand that unhandledrejection is generated when the microtask queue is complete: the

The referrerPolicy option sets general… the referrer option that allows to set the exact Referer value, referrerPolicy tells the browser general

We can easily generate partial functions such as for today’s logs.

It’s forbidden to generate “custom” clipboard events with dispatchEvent in all browsers except Firefox

Its reading methods read* do not generate events, but rather return a result, as regular functions do

Sending a form with Blob data.As we’ve seen in the chapter Fetch, it’s easy to send dynamically generated

But generally lookaround is more convenient. Lookaround types: Pattern type matches X(?

but one thing we know for sure: if the pointer “officially” entered an element (mouseover event generated… As you can see, the only generated events are the ones related to moving the pointer in and out of the

Scripts that are generated dynamically with document.createElement('script') and then added to the webpage… There’s also a keepalive flag for doing such “after-page-left” requests in fetch method for generic

Decorators and function properties.It is generally safe to replace a function or a method with a decorated… The generic call forwarding is usually done with apply:

<html> and <body>, and add the required <head>, and the DOM will be: While generating… Later, when you know them in general, read the docs and pick up the rest.

For example, getListContent below generates a fragment with <li> items, that are later inserted… The html string can be dynamically generated, so it’s kind of flexible.

Sec-WebSocket-Key – a random browser-generated key, used to ensure that the server supports WebSocket… Rate limiting.Imagine, our app is generating

The JavaScript engine tracks such rejections and generates a global error in that case.

Specifications The BOM is a part of the general HTML specification.

are other ways to do that: we can load content dynamically with fetch and show it in a dynamically generated… In this example, we generate popup content from JavaScript:

It’s generally not used in modern scripts, but still lurks in the old ones.

As a general rule, local styles work only inside the shadow tree, and document styles work outside of