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Arrays provide a lot of methods.… We expect to have a shorter array now. So, special methods should be used.… The arr.splice method is a Swiss army knife for arrays.… . concat.The method arr.concat creates a new array that includes values from other arrays and additional… Most methods support “thisArg”.Almost all array methods that call functions – like find, filter, map,

Methods that work with the end of the array: pop Extracts the last element of the array and returns… Methods that work with the beginning of the array: shift Extracts the first element of the array and… It is auto-adjusted by array methods. If we shorten length manually, the array is truncated.… We will continue with arrays and study more methods to add, remove, extract elements and sort arrays… in the next chapter Array methods.

Typed arrays behave like regular arrays: have indexes and are iterable.… If an Array, or any array-like object is given, it creates a typed array of the same length and copies… TypedArray methods.TypedArray has regular Array methods, with notable exceptions.… No concat method.… These methods allow us to copy typed arrays, mix them, create new arrays from existing ones, and so on

JavaScript provides methods: JSON.stringify to convert objects into JSON.… Namely: Function properties (methods). Symbolic keys and values.… Fortunately, we can use a function instead of an array as the replacer.… can include other objects and arrays.… Both methods support transformer functions for smart reading/writing.

In this article we’ll cover various methods that work with regexps in-depth. str.match(regexp).The method… If there are no matches, we don’t get an empty array, but null.… We can make a regular array from it using Array.from.… Unlike previous methods, it’s called on a regexp, not on a string.… Or instead of calling methods on regexp, use string methods str.match/search/..., they don’t use lastIndex

They are supported for: Map Set Array Plain objects also support similar methods, but the syntax is… ) – returns an array of keys.… The second difference is that Object.* methods return “real” array objects, not just an iterable.… Transforming objects.Objects lack many methods that exist for arrays, e.g. map, filter and others.… Use array methods on that array, e.g. map, to transform these key/value pairs.

E.g. we would like to work with range using array methods. How to achieve that?… Array.from.There’s a universal method Array.from that takes an iterable or array-like value and makes… Then we can call array methods on it.… Such objects may also have other properties and methods, but lack the built-in methods of arrays.… use array methods on it.

Built-in classes like Array, Map and others are extendable also.… If we’d like built-in methods like map or filter to return regular arrays, we can return Array in Symbol.species… For instance, Array extends Object.… For example, both Array and Date inherit from Object, so their instances have methods from Object.prototype… But Array.

In the first chapter of this section, we mentioned that there are modern methods to setup a prototype… The modern methods to get/set a prototype are: Object.getPrototypeOf(obj) – returns the [[Prototype]… Although, there’s a special method for this too: Object.create(proto[, descriptors]) – creates an empty… The Object.create method… Unexpected things also may happen when assigning to obj.toString, as it’s a built-in object method.

For instance, when we create an array [1, 2, 3], the default new Array() constructor is used internally… If two libraries add a method String.prototype.show, then one of them will be overwriting the method… For instance, if we’re making an array-like object, we may want to copy some Array methods to it.… It doesn’t check if the object is indeed an array. Many built-in methods are like that.… __proto__ to Array.prototype, so all Array methods are automatically available in obj.

Besides that, Map has a built-in forEach method, similar to Array:… There’s Object.fromEntries method that does the reverse: given an array of [key, value] pairs, it creates… But the performance would be much worse, because this method walks through the whole array checking every… Methods and properties: new Map([iterable]) – creates the map, with optional iterable (e.g. array) of… Methods and properties: new Set([iterable]) – creates the set, with optional iterable (e.g. array) of

…And for objects that are both iterable and array-like, such as a real array, we can use any of them,… a real array.… We take (borrow) a join method from a regular array ([].join) and use [].join.call to run it in the context… It’s intentionally written in a way that allows any array-like this (not a coincidence, many methods… It is quite common to take array methods and apply them to arguments.

There are 6 static methods in the Promise class. We’ll quickly cover their use cases here.… The new promise resolves when all listed promises are resolved, and the array of their results becomes… A common trick is to map an array of job data into an array of promises, and then wrap that into Promise.all… But if any of those objects is not a promise, it’s passed to the resulting array “as is”.… to resolve and returns an array of their results.

array: At index 0: the full match.… matchAll is a new method, polyfill may be needed The method matchAll is not supported in… To get them, we should search using the method str.matchAll(regexp).… We can turn it into a real Array using Array.from.… The method str.matchAll always returns capturing groups.

The fetch method allows to track download progress.… method to get the result.… We gather response chunks in the array chunks.… At the end, we have chunks – an array of Uint8Array byte chunks.… Then use .set(chunk, position) method to copy each chunk one after another in it.

In JavaScript, they are available via the RegExp object, as well as being integrated in methods of strings… The method str.match(regexp) finds all matches of regexp in the string str.… It has 3 working modes: If the regular expression has flag g, it returns an array of all matches:… If there are no matches, we don’t receive an empty array, but instead receive null.… Full information about the methods is given in the article Methods of RegExp and String. Summary.

…And with built-in classes like Array… That’s because Array prototypically inherits from Object.… We can also set a custom logic in the static method Symbol.hasInstance.… boolean, it will be [object Boolean] For null: [object Null] For undefined: [object Undefined] For arrays… : [object Array] …etc (customizable).

Arrays allow us to gather data items into an ordered list.… Array destructuring.Here’s an example of how an array is destructured into variables:… It looks great when combined with split or other array-returning methods:… However, the array itself is not modified.… of the remaining array elements.

For instance [[Get]], the internal method to read a property, [[Set]], the internal method to write a… We don’t have to override value-adding array methods like push and unshift, and so on, to add checks… Its methods are minimal wrappers around the internal methods.… Built-in methods access them directly, not via [[Get]]/[[Set]] internal methods.… The built-in method Map.prototype.set method tries to access the internal property this.

And also, how to pass arrays to such functions as parameters.… The dots literally mean “gather the remaining parameters into an array”.… But the downside is that although arguments is both array-like and iterable, it’s not an array.… It does not support array methods, so we can’t call arguments.map(...) for example.… The list of characters is passed to array initializer [...str].

DOM collections.As we can see, childNodes looks like an array.… But actually it’s not an array, but rather a collection – a special array-like iterable object.… Array methods won’t work, because it’s not an array:… if we want array methods:… Changing DOM needs other methods. We will see them in the next chapter.

similar to Blob: fileParts – is an array… The constructor: The main methods:… The choice of read* method depends on which format we prefer, how we’re going to use the data.… Its reading methods read* do not generate events, but rather return a result, as regular functions do… In addition to Blob methods and properties, File objects also have name and lastModified properties,

There are additional searching methods for that. document.getElementById or just id.If an element has… In real life document.getElementById is the preferred method.… The method comes in handy when we are iterating over elements (like in an array or something) and trying… It’s like a fixed array of elements.… Summary.There are 6 main methods to search for nodes in DOM: Method Searches by...

As defined in Wikipedia, a mixin is a class containing methods that can be used by other classes without… In other words, a mixin provides methods that implement a certain behavior, but we do not use it alone… As super looks for parent methods in [[HomeObject]].… …And the method .off(name, handler) that removes the handler listener.… Mixins may become a point of conflict if they accidentally overwrite existing class methods.

A department may have an array of staff.… The 1st case is the base of recursion, the trivial case, when we get an array.… chapter Array methods to get the sum of the array.… …But there’s a problem with arrays.… In an array that’s easy: arr[n] is a direct reference.

Usually, properties of an object or elements of an array… For instance, if we put an object into an array, then while the array is alive, the object will be alive… WeakMap does not support iteration and methods keys(), values(), entries(), so there’s no way to get… WeakMap has only the following methods: weakMap.set(key, value) weakMap.get(key) weakMap.delete(key)… For that reason, methods that access all keys/values are not supported.

To perform the actual search, there are following methods.… The price is not an array, so multiEntry flag is not applicable.… Then getAll will fail to get all records as an array. What to do?… It creates a global idb object with promisified IndexedDB methods.… Then, to search by a key, call methods on the object store directly.

For instance: arr.forEach(func) – func is executed by forEach for every array item. setTimeout(func)… Arrow functions have no “this”.As we remember from the chapter Object methods, "this", arrow… For instance, we can use it to iterate inside an object method:… Here in forEach, the arrow function is used, so this.title in it is exactly the same as in the outer method

constructor syntax is: blobParts is an array… Call canvas method .toBlob(callback, format, quality) that creates a Blob and runs callback with it when… The Blob interface’s stream() method returns a ReadableStream which upon reading returns the data contained… Methods that perform web-requests, such as XMLHttpRequest, fetch and so on, can work with Blob natively… can easily convert between Blob and low-level binary data types: We can make a Blob from a typed array

There’s a special method append for that: document.body.append(div).… So, these methods can only be used to insert DOM nodes or text pieces.… Old-school insert/remove methods.… These methods come from really ancient times.… But usually the returned value is not used, we just run the method.

we really need to make constant object properties, it’s also possible, but using totally different methods… There are also other methods of cloning an object, e.g. using the spread syntax clone = {...user}, covered… There’s structuredClone method that implements deep cloning. structuredClone.The call structuredClone… can clone most data types, such as objects, arrays, primitive values.… To handle such complex cases we may need to use a combination of cloning methods, write custom code or

These methods are not a part of JavaScript specification.… But most environments have the internal scheduler and provide these methods.… For instance, Node.js returns a timer object with additional methods.… Again, there is no universal specification for these methods, so that’s fine.… The nested setTimeout is a more flexible method than setInterval.

Right now, there’s another, more modern method fetch, that somewhat deprecates XMLHttpRequest.… specifies the main parameters of the request: method – HTTP-method.… This method opens the connection and sends the request to server.… Some request methods like GET do not have a body.… There’s another object, without methods, exclusively to track upload events: xhr.upload.

Both storage objects provide the same methods and properties: setItem(key, value) – store key/value… If the key is user-generated, it can be anything, like length or toString, or another built-in method… Looping over keys.As we’ve seen, the methods provide “get/set/remove by key” functionality.… One way is to loop over them as over an array:… Properties and methods are the same, but it’s much more limited: The sessionStorage exists only within

As we can see from the name of the method, that path is taken after the composition.… , for a click on <span slot="username">, a call to event.composedPath() returns an array… That’s the similar principle as for other methods that work with shadow DOM.

node, subtree – in all descendants of node, attributes – attributes of node, attributeFilter – an array… When exactly should we run that highlighting method?… We’ll study methods for that later in the tutorial.… Additional methods.There’s a method to stop observing the node: observer.disconnect() – stops the observation… These methods can be used together, like this:

The function code execution hasn’t started yet: The main method… Generators are iterable.As you probably already guessed looking at the next() method, generators are… In the code above, ...generateSequence() turns the iterable generator object into an array… That works, because range[Symbol.iterator]() now returns a generator, and generator methods… are exactly what for..of expects: it has a .next() method that returns values in the form {value: .

The deref() method returns the referent-object that the WeakRef points to, if the object is still in… If the object has been deleted by the garbage collector, then the deref() method will return undefined… being collected by the garbage collector solely based on their presence in the cache or associative array… If there is no entry in the cache with the requested key, or deref() method returns undefined (meaning… If the deref() method returns undefined, it means that the DOM-element has been deleted from memory.

They also provide methods to call as such.… So here we’ve made an object john with the method sayHi.… It would be great to access them using methods.… Thus, they provide different sets of methods.… That method runs and returns a new string (shown by alert).

A function that is a property of an object is called its method.… So, here we’ve got a method sayHi of the object user.… Method shorthand.There exists a shorter syntax for methods in an object literal:… To access the object, a method can use the this keyword.… Methods allow objects to “act” like object.doSomething().

That’s the array of subprotocols, e.g. if we’d like to use SOAP or WAMP:… WebSocket .send() method can send either text or binary data.… The method for that is: code is a… Methods: socket.send(data), socket.close([code], [reason]).

We can also assign a method to the class as a whole. Such methods are called static.… It’s not a method of an article, but rather of the whole class.… Another example would be a so-called “factory” method.… Once again, that’s not a method of an article, but a method of the whole class.… For example, a method for comparison Article.compare(article1, article2) or a factory method Article.createTodays

We can use either a regular expression or array functions to do that.… The full list of safe HTTP methods is in the RFC7231 specification.… These are the methods that should be used for reading, but not writing the data.… Following a link is always GET, the safe method.… Additionally, JavaScript methods for network requests do not perform any navigation.

A popup window is one of the oldest methods to show additional document to user.… Only popups To prevent abuse, the browser usually blocks these methods.… Move/resize methods do not work for maximized/minimized windows.… Focus/blur on a window.Theoretically, there are window.focus() and window.blur() methods to focus/unfocus… Methods focus() and blur() allow to focus/unfocus a window. But they don’t work all the time.

The method form.submit() allows to initiate form sending from JavaScript.… the demo: Method

Internal and external interface.In object-oriented programming, properties and methods are split into… two groups: Internal interface – methods and properties, accessible from other methods of the class… External interface – methods and properties, accessible also from outside the class.… Until now we were only using public properties and methods.… _power from the methods of the new class. So protected fields are naturally inheritable.

Here is an example of all three methods:

We do something in our method, but call the parent method before/after it or in the process.… A method, such as longEar.eat, knows its [[HomeObject]] and takes the parent method from its prototype… But for objects, methods must be specified exactly as method(), not as "method: function()"… When overriding another method: We can use super.method() in a Child method to call Parent method.… That’s how super resolves parent methods.

class methods, which would result in a syntax error.… The function code is taken from the constructor method (assumed empty if we don’t write such method).… So the object has access to class methods.… Class methods are non-enumerable.… Previously, our classes only had methods.

No matter where the method is found: in an object or its prototype.… In a method call, this is always the object before the dot.… Where is the method rabbit.hasOwnProperty coming from? We did not define it.… So methods always work with the current object even if they are inherited.… All other key/value-getting methods only operate on the object itself.