Detailed description of the javascript String concatenation Method

This article will give you a summary of the javascript String concatenation method. In js, you can not only directly use + to connect strings, but also use related functions. The following is a tutorial.

String concatenation is common in JS. Sometimes it is troublesome to splice long strings. For example, an html string;

The Code is as follows:	Copy code
Var str = "aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa "; Var str = "aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa ";

The editor is limited in width. To make it readable, you must wrap the string. However, if you wrap the text below, an error is reported.

The Code is as follows:	Copy code
Var str = "aaaaaaaaaaaaaaaaaaa Aaaaaaaaaaaaaaaaaaaaaa Aaaaaaaaaaaaaaaaaaaaaa "; var str =" aaaaaaaaaaaaaaaaaaa Aaaaaaaaaaaaaaaaaaaaaa Aaaaaaaaaaaaaaaaaaaaaa ";

At this time, you need to splice strings. The most basic method is:

The Code is as follows:	Copy code
Var str = "aaaaaaaaaaaaaaaaaa" + "Aaaaaaaaaaaaaaaaaaaaaa" + "Aaaaaaaaaaaaaaaaaaaaaaa"; var str = "aaaaaaaaaaaaaaaaaa" + "Aaaaaaaaaaaaaaaaaaaaaa" + "Aaaaaaaaaaaaaaaaaaaaaaa ";

If there are only two or three rows, it would be better to have dozens of rows, which is not only time-consuming and laborious, but also prone to errors.

String concatenation techniques, using Arrays for character concatenation:

 

The Code is as follows:	Copy code
Var strArr = []; StrArr. push ("aaaaaaaaaaaaaaaaaa "); StrArr. push ("aaaaaaaaaaaaaaaaaaaaaa "); StrArr. push ("aaaaaaaaaaaaaaaaaaaaaaa "); StrArr. join (""); var strArr = []; StrArr. push ("aaaaaaaaaaaaaaaaaa "); StrArr. push ("aaaaaaaaaaaaaaaaaaaaaa "); StrArr. push ("aaaaaaaaaaaaaaaaaaaaaaa "); StrArr. join ("");

This method reduces the probability of errors, but the amount of work is still small.

More convenient String concatenation methods:
Line feed directly in the string will produce an error, but if you add a backslash "" after each line, it will not produce an error;

 

The Code is as follows:	Copy code
Var str = "aaaaaaaaaaaaaaaaaa Aaaaaaaaaaaaaaaaaaaaaa Aaaaaaaaaaaaaaaaaaaaaaa "; // Do not add the backslash var str = "aaaaaaaaaaaaaaaa" to the last line Aaaaaaaaaaaaaaaaaaaaaa Aaaaaaaaaaaaaaaaaaaaaaa ";

// The last line does not need to be added with a backslash. Of course, this method also has a disadvantage, that is, it cannot be followed by a single line comment.

As for the performance comparison between these methods, I don't think we should consider it too much. Unless there are thousands of lines of String concatenation, the performance gap will be negligible; the readability of the program should be put in front.