als-path-to-regexp
v1.1.0
Published
A custom utility for converting URL path patterns to regular expressions, supporting dynamic segments, wildcards, and special character escaping.
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als-path-to-regexp
Overview
The pathToRegexp
function is designed to convert a URL path pattern into a regular expression, which can be used to match and extract parameters from URLs. It handles dynamic segments, wildcards, and escaping special characters.
install and import module
Install:
npm i als-path-to-regexp
Import:
const pathToRegexp = require('als-path-to-regexp')
Function Signature
function pathToRegexp(path, keys = [])
Parameters
path
: A string representing the URL path pattern.keys
: (Optional) An array to store the keys of the parameters.
If an invalid path is provided to the pathToRegexp function, an error is thrown. This ensures that only valid paths are processed, preventing potential issues with incorrect or unsafe regular expressions.
For example, if a path like /user/{id}/: is passed, which doesn't meet the required pattern, the function will throw an error stating that the path is not valid. This safeguard is crucial for maintaining the reliability and security of the code.
Return Value
The function returns an object containing the following properties:
regexp
: A RegExp object built from the provided path.keys
: An array of keys for the parameters found in the path.match
: A function that takes a URL and returns an object with extracted parameters ornull
if there is no match.segments
: The array of segments from the path.
The match
Function
The match
function returned by pathToRegexp
is used to test a URL against the generated regular expression and extract parameters.
Limitations
- When the path pattern ends with a wildcard (
*
), the generated regular expression and thematch
function can match multiple URL structures, making it less specific. - The
match
function will returnnull
if the URL does not fit the pattern defined by the regular expression.
Regular Expression (regexp
) and Escaping Characters
The pathToRegexp
function automatically escapes special characters that have specific meanings in regular expressions. This ensures that the literal characters are matched in the URL rather than being interpreted as special regex operators.
Escaped Characters
Characters that are escaped include: .
, *
, +
, ?
, ^
, ${}
, ()
, |
, []
, \
.
Example Usage
const { regexp, match } = pathToRegexp("/user/{id}");
const url = "/user/123";
if (regexp.test(url)) {
const params = match(url);
console.log(params); // { id: '123' }
}
Wildcard Patterns
Wildcard patterns (paths ending with *
) create regular expressions that match a broader range of URLs. This is useful for matching a set of URLs under a common base path.
Example
const { match } = pathToRegexp("/api/*");
console.log(match("/api/users")); // Matches
console.log(match("/api/products")); // Matches
The pathToRegexp
function is an essential tool for creating dynamic route handling in web applications, providing flexibility and precision in URL pattern matching.