There are additional searching methods for that.
document.getElementById or just id.If an element has… So it’s faster and also shorter to write.
matches.Previous methods were searching the DOM.… The elem itself is also included in the search.… If it matches the selector, then the search stops, and the ancestor is returned.… Summary.There are 6 main methods to search for nodes in DOM:
Method
Searches by...
The flag y allows to perform the search at the given position in the source string.… So, how to search for a regexp exactly at the given position?… We can manually set lastIndex to 4, to start the search from the given position!… The flag y makes regexp.exec to search exactly at position lastIndex, not “starting from” it.… more time than the search with flag y, that checks only the exact position.
Regular expressions are patterns that provide a powerful way to search and replace in text.… There are only 6 of them in JavaScript:
i
With this flag the search is case-insensitive: no difference… between A and a (see the example below).
g
With this flag the search looks for all matches, without… More about that in the chapter Unicode: flag "u" and class \p{...}.
y
“Sticky” mode: searching… substring search.
It’s used mainly to search for all matches with all groups.… The swiss army knife for searching and replacing.… We can use it without regexps, to search and replace a substring:… We can use regexp.exec to search from a given position by manually setting lastIndex.… To work around that, we can set regexp.lastIndex = 0 before each search.
They are used to do more powerful searches.… Here’s what a search for a slash '/' looks like:… The similar search… That’s why the search doesn’t work!… To search for special characters [ \ ^ $ . | ?
Searching at line start ^.In the example below the text has multiple lines.… Searching at line end $.The dollar sign $ behaves similarly.… Searching for \n instead of ^ $.To find a newline, we can use not only anchors ^ and $, but also the… Here we search for \d\n instead of \d$:
href is the full url, same as url.toString()
protocol ends with the colon character :
search… …”.Let’s say we want to create a url with given search params, for instance, https://google.com/search… It provides convenient methods for search parameters:
append(name, value) – add the parameter by name… …On the other hand, if we look at a single URL component, such as a search parameter, these characters… So we should use only encodeURIComponent for each search parameter, to correctly insert it in the URL
We should understand how the search works very well if we plan to look for something more complex than… These common words do not make it obvious why the regexp fails, so let’s elaborate how the search works… If there were a quote there, then the search would end, but the last character is 'e', so there’s no… ':
And now the search goes differently.… As we’ve seen, the lazy mode is not a “panacea” from the greedy search.
Although, it’s often best to use an internet search instead.… Just use “MDN [term]” in the query, e.g. https://google.com/search?… q=MDN+parseInt to search for the parseInt function.
Example: domain.Let’s make something more complex – a regular expression to search for a website domain… Searching for all matches with groups: matchAll.… To get them, we should search using the method str.matchAll(regexp).… The call to matchAll does not perform the search.… The search is performed each time we iterate over it, e.g. in the loop.
By key.First let’s deal with the first type of search: by key.… To perform the actual search, there are following methods.… Now, when we want to search for a given price, we simply apply the same search methods to the index:… So when we do the search, the results are also sorted by price.… As we remember, indexes allow to search by an object field.
Several characters or character classes inside square brackets […] mean to “search for any character… The pattern searches… In the example below we’re searching for "x" followed by two digits or letters from A to F:… Here [0-9A-F] has two ranges: it searches
If it’s not so, then the potential match is skipped, and the search continues.… If both tests passed, then the X is a match, otherwise continue searching.… Y), it means “search X, but only if not followed by Y”.
To be fair, let’s note that some regular expression engines can handle such a search… What happens during the search of ^(\d+)*$ in the line 123456789z (shortened a bit for clarity, please… Trying each of them is exactly the reason why the search takes so long.… As there are many such combinations (we’ve seen it with digits), the search takes a lot of time.… The search process without backtracking is simpler.
And also Unicode property search becomes available, we’ll get to it next.… We can search for characters with a property, written as \p{…}.… Unicode properties can be used in the search: \p{…}.
The optional second parameter allows us to start searching… To look for the next occurrence, let’s start the search from position 2:… substr, position)
There is also a similar method str.lastIndexOf(substr, position) that searches… The optional second argument of str.includes is the position to start searching… Strings also have methods for doing search/replace with regular expressions.
Static methods are also used in database-related classes to search/save/remove entries from the database… So if a field is not found in B, the search continues in A.
Searching in array.Now let’s cover methods that search in an array.
indexOf/lastIndexOf and includes.The… Usually, these methods are used with only one argument: the item to search.… By default, the search is from the beginning.… If it returns true, the search is stopped, the item is returned.… The arr.findLastIndex method is like findIndex, but searches from right to left, similar to lastIndexOf
When the regexp engine (program module that implements searching for regexps) comes across \b, it checks
Let’s say, we want to make a menu with buttons “Save”, “Load”, “Search” and so on.… And there’s an object with methods save, load, search… How to match them?
Example: regexp for time.In previous articles there was a task to build a regexp for searching time in
The lookup of this is made exactly the same way as a regular variable search: in the outer lexical environment
They are unknown to search engines, and accessibility devices can’t handle them.… E.g, a search engine would be interested to know that we actually show a time.
When the code wants to access a variable – the inner Lexical Environment is searched first, then the… In this example the search proceeds as follows:
For the name variable, the alert inside say finds it… Now when the code inside counter() looks for count variable, it first searches
To find something, it’s often convenient to use an internet search “WHATWG [term]” or “MDN [term]”, e.g
We can search by these properties as well. That requires flag u, covered in the next article.
For errors in network operations we may need HttpError, for database operations DbError, for searching
The moment our DOM is ready, we can search for elements pre[class*="language"] and call Prism.highlightElem
If you came to this article searching for other types of loops, here are the pointers:
See for…in to
Search engines follow <a href="..."> links while indexing.
outsiders, other programmers who use our package, should not meddle with its internal structure, search
No one will be able to find it using “search” of the editor.
It provides element-level navigation like nextElementSibling, children and searching methods like getElementsByTagName
Similarly, when searching for a key in the cache, there is a chance that the value has been deleted by
When we read admin.name, as admin object doesn’t have such own property, the search goes to its prototype