JavaScript-CheatSheet-en
Symbols
Term | Description |
. | (period) Matches any single character, except for line breaks. |
* | Matches the preceding expression 0 or more times. |
+ | Matches the preceding expression 1 or more times. |
? | Preceding expression is optional (Matches 0 or 1 times). |
^ | Matches the beginning of the string. |
$ | Matches the end of the string. |
Character groups
Term | Description |
\d | Matches any single digit character. |
\w | Matches any word character (alphanumeric & underscore). |
[XYZ] | Character Set: Matches any single character from the character within the brackets. You can also do a range such as [A-Z] |
[XYZ]+ | Matches one or more of any of the characters in the set. |
| Inside a character set, the ^ is used for negation. In this example, match anything that is NOT an uppercase letter. |
Flags:
There are five optional flags. They can be used separately or together and are placed after the closing slash. Example: /[A-Z]/g I’ll only be introducing 2 here.
Term | Description |
g | Global search |
i | case insensitive search |
Advanced
Term | Description |
(x) | Capturing Parenthesis: Matches x and remembers it so we can use it later. |
(?:x) | Non-capturing Parenthesis: Matches x and does not remembers it. |
x(?=y) | Lookahead: Matches x only if it is followed by y. |
The reduce() method is used to apply a function to each element in the array to reduce the array to a single value.
