Javascript Strings

Latest revision as of 17:01, 11 September 2013

Although the String object is not directly supported by Yate's Javascript these methods are applicable to most non-object variables.

Note that these are not real properties of strings and cannot be enumerated!

• length

Property that describes the length of a string as a decimal number.

Returns numeric length of string

x="abcd";
Engine.output(x.length);

4

• charAt(pos)

Function that returns a character at a certain 0-based position in string.

Returns a string containing a single character or empty if pos is out of bounds.

x="abcd";
Engine.output(x.charAt(3));

d

• indexOf(str)

Function that returns the position of a substring in another string.

Returns 0-based position of str or -1 if str is not found

x="abcd";
Engine.output(x.indexOf("bc"));

1

• substr(offs,len)

Function that returns a substring.

Returns a string that starts at 0-based position offs and has at most len characters

x="abcd";
Engine.output(x.substr(1,2));

bc

• substr(offs)

Function that returns a substring.

Returns a string that starts at 0-based position offs to the end of the original string

x="abcd";
Engine.output(x.substr(2));

cd

• match(reg)

Function that matches a string against a Regular Expression.

Returns an Array holding the match results and some extra information:

• [0] holds the whole matching string
• [1]... hold the captured substrings
• index holds the 0-based index of the first matching character
• input holds the RegExp object used in match

If the string does not match the regular expression reg then the function returns null.

x="abc123";
m = x.match(/([0-9])/);
Engine.output((typeof m) + " index=" + m.index + " input=" + m.input);

object index=3 input=([0-9])

• toLowerCase()

Function that converts a string to lower case.

Returns the string converted to lower case characters.

x="AbCd";
Engine.output(x.toLowerCase());

abcd

• toUpperCase()

Function that converts a string to upper case.

Returns the string converted to upper case characters.

x="AbCd";
Engine.output(x.toUpperCase());

ABCD

• trim()

Function that removes leading and trailing spaces from a string.

Returns the string with all initial and final whitespaces removed.

x="  a bc d ";
Engine.output(">" + x.trim() + "<");

>a bc d<

• sqlEscape()

Function that performs SQL escaping on a string.

Note that backslash escaping is an SQL extension

x="a'b'c\\backslash";
Engine.output(x.sqlEscape());

a''b''c\\backslash

• startsWith(str)

Function that checks if a string starts with a specific substring.

Returns true if str is the prefix of the string.

x="abcd";
Engine.output(x.startsWith("ab"));

true

• endsWith(str)

Function that checks if a string ends with a specific substring.

Returns true if str is the suffic of the string.

x="abcd";
Engine.output(x.endsWith("bcd"));

true

• split(sep)

Function that splits a string into an Array at a separator.

Returns an Array object holding the string fragments.

x="abc,def,xyz";
a=x.split(",");
Engine.output("[0]=" + a[0] + " [1]=" + a[1] + " [2]=" + a[2]);

[0]=abc [1]=def [2]=xyz

• toString()

Function that converts a number to string using numbering base 10.

x=1234;
s=x.toString();
Engine.output((typeof s) + " " + s)

string 1234

• toString(base)

Function that converts a number to string using a specified numbering base.

x=1234;
s=x.toString(16);
Engine.output((typeof s) + " " + s)

string 4d2