In JavaScript, the includes()
method can be used to determine whether a string contains a specific value as a substring. The method returns a boolean value, true
if the string includes the specified value, and false
otherwise.
Here are a few examples to illustrate its usage:
'JavaScript'.includes('Script') // true
'JavaScript'.includes('script') // false
'JavaScript'.includes('JavaScript') // true
'JavaScript'.includes('aSc') // true
'JavaScript'.includes('C++') // false
In the first example, 'JavaScript'
contains the substring 'Script'
, so the includes()
method returns true
. However, it is case-sensitive, so in the second example, 'script'
is not found within the string 'JavaScript'
, resulting in false
.
Furthermore, the includes()
method also has an optional second parameter, which specifies the position from where the search should begin. Here’s an example:
'a nice string'.includes('nice') // true
'a nice string'.includes('nice', 3) // false
'a nice string'.includes('nice', 2) // true
In the first example, 'nice'
is found in the string 'a nice string'
, resulting in true
. However, in the second example, the search starts from the position 3, which means it skips the occurrence of 'nice'
and returns false
. Finally, in the third example, the search starts from position 2, and 'nice'
is found, returning true
.
By utilizing the includes()
method, you can easily check whether a string includes a specific substring. Remember to pay attention to case-sensitivity and explore the optional second parameter for advanced searching.