The page loaded into the browser is represented by a tree of elements, many of whose properties are plain text. Information coming from the server and sent to it is also text. Transferring the center of gravity of processing to the browser makes the site more efficient, reduces the load on the server and gives the latter the opportunity to serve more visitors faster.
The split JavaScript method splits the string into components according to a specific separator and forms an array. The join method joins the elements of an array into a string through a given string. The delimiter can be a character, string, or regular expression.
Split syntax and meaning
JavaScript method format split (string, limit). The first parameter is the delimiter itself. The second parameter is the number of elements to be generated in the output array.
In the first example, the delimiter is not specified either in the JavaScript str.split construct or in the join method of the aStr array obtained by splitting the string by the supposed delimiter ",". Merging array elements is also performed by the symbol ",".
The second example contains an error: instead of a comma, a period is indicated between the letters "d" and "e". The use of a regular expression, example 3, allows avoiding probable errors and at the same time removing extra spaces. In the last example, between the essential elements of a string can be:
There can be any number of spaces before and after the separator. The result is a “clean” string (res) and an array (aStr) containing only three-letter names of the months.
Select content and separators
In some cases, you may need to not only parse the string through the specified delimiter, but also select it too.
In the example (4), the symbol `` 'is selected as a separator during merging because different separators are found in the original line. It is doubtful that the resulting array is convenient to use when there are various delimiters in it, but the scope can determine different requirements for how to parse and assemble strings.
However, example (4) shows that JavaScript split returns commas, periods, and other characters as elements of an array. In the example (5), numbers are used as delimiters. Here you can manipulate, for example, parsing a bibliography, fetch lists with numbering, and parse CSS rules or HTML rules.
Features of String Functions
A characteristic feature of modern programming, especially Internet technologies, is the description and use of variables without type. The type of a variable is determined by the syntax in which it is applied.
This point allows you to use join & split JavaScript as a great tool for transforming any data into a string representation. Next, the data row is placed in a file or cell in the database table, and, if necessary, is returned and parsed to the necessary data.
Very often there are situations when a string cannot be formed during the analysis of primary data. Using stack operations pop () and push it is possible to form data arrays without attaching any value to how, at what point in time, and which particular was the subject of analysis.
The generated data array can be merged into a single line with one separator, but immediately disassembled differently. The simplest example: an encoded signal arrives at the input, each element of which corresponds to an array of transcripts or explanations of the codes.
Parsing the input string, the programmer gets the indices of the associative array, which contains the necessary decryption or explanation.
A good use for split JavaScript is to convert hexadecimal numbers to decimal and vice versa. The algorithm does not even need to be composed: parsing a number and a transformation formula. No loop, no analysis of the input number for correctness.
Object Oriented Join & Split Applications
In addition to the classic serialization and deserialization options, the join & split JavaScript methods can be used as the main syntactic constructions for implementing the functionality of objects oriented to the field of application and programming the “relations” of objects between themselves.
To create instances of objects, designers are used that read character strings and cells of database tables, but outside of these constructors it is not so important where the internal data of the instance is generated from. Moreover, as a result of reading the object, an instance of any type can be formed.
If instances of created objects are placed in an array, then, using features, for example, of the pop () method, you can work with the array as an object of any type. This method extracts an element from an array, and the next time it retrieves the next one. The sequence of these extracts makes it possible to work with all instances of the array in the same way, without attaching importance to which object is in operation.