Encoding and Decoding URI and URI components is a usual task in web development while making a GET request to API with query params. Many times construct a URL string with query params and in order to understand it, the response server needs to decode this URL. Browsers automatically encode the URL i.e. convert some special characters to other reserved characters and then make the request. For eg: The space character ” ” is either converted to + or %20.
Example:
- Open www.google.com and write a search query “geeks for geeks”.
- After search results appear, observe the browser’s URL bar. The browser URL will consist of %20 or + sign in place of space.
- The URL will be displayed like: https://www.google.com/search?q=geeks%20for%20geeks or https://www.google.com/search?q=geeks+for+geeks
Note: The browser converted the spaces into + or %20 signs automatically.
Encoding a URL: Encoding in Javascript can be achieved using:
JavaScript encodeURI Function
The encodeURI() function is used to encode complete URI. This function encodes the special character except for (, / ?: @ & = + $ #) characters.
Syntax:
encodeURI( complete_uri_string );
const encodedURL = encodeURI(url); console.log(encodedURL) |
https://www.google.com/search?q=geeks%20for%20geeks
JavaScript encodeURIComponent() Function
The encodeURIComponent() function is used to encode some parts or components of URI. This function encodes the special characters. In addition, it encodes the following characters: , / ? : @ & = + $ #
Syntax:
encodeURIComponent( uri_string_component );
const component = "geeks for geeks" ;
const encodedComponent = encodeURIComponent(component); console.log(encodedComponent); |
geeks%20for%20geeks
JavaScript escape() function
This function takes a string as a single parameter & encodes the string that can be transmitted over the computer network which supports ASCII characters. Encoding is the process of converting plain text into ciphertext.
Syntax:
escape( string )
Note: The escape() function only encodes the special characters, this function is deprecated.
Exceptions: @ – + . / * _
const encodedURL = encodeURI(url); // encoding using encodeURI
console.log(encodedURL) console.log( "<br>" + escape(url)); //encoding using escape
|
https://www.google.com/search?q=geeks%20for%20geeks <br>https%3A//www.google.com/search%3Fq%3Dgeeks%20for%20geeks
Decoding a URL: Decoding in Javascript can be achieved using
- JavaScript decodeURI() Function
- JavaScript decodeURIComponent() Function
- JavaScript unescape() Function
JavaScript decodeURI() Function
The decodeURI() function is used to decode URI generated by encodeURI().
Syntax:
decodeURI( complete_encoded_uri_string )
Example: This example describes the decodeURI() function of Javascript.
const decodedURL = decodeURI(url); console.log(decodedURL) |
https://www.google.com/search?q=geeks for geeks
JavaScript decodeURIComponent() Function
The decodeURIComponent() function is used to decode some parts or components of URI generated by encodeURIComponent().
Syntax:
decodeURIComponent( encoded_uri_string_component )
Example: This example describes the decodeURIComponent() of Javascript.
const component = "geeks%20for%20geeks"
const decodedComponent = decodeURIComponent(component); console.log(decodedComponent) |
geeks for geeks
JavaScript unescape() Function
This function takes a string as a single parameter and uses it to decode that string encoded by the escape() function. The hexadecimal sequence in the string is replaced by the characters they represent when decoded via unescape() function.
Syntax:
unescape(string)
Note: This function only decodes the special characters, this function is deprecated.
Exceptions: @ – + . / * _
const encodedURL = encodeURI(url); console.log(encodedURL) console.log(escape(url)); console.log(decodeURI(encodedURL)); console.log(unescape(encodedURL)); |
https://www.google.com/search?q=geeks%20for%20geeks https%3A//www.google.com/search%3Fq%3Dgeeks%20for%20geeks https://www.google.com/search?q=geeks for geeks https://www.google.com/search?q=geeks for ...
Difference decodeURIComponent and decodeURI:
decodeURIComponent | decodeURI | |
---|---|---|
Definition | The decodeURIComponent() function is used to decode some parts or components of URI generated by encodeURIComponent(). | Decoding in Javascript can be achieved using decodeURI function. |
Syntax | decodeURIComponent( encoded_uri_string_component ) | decodeURI( complete_encoded_uri_string ) |
Special Character Encoding | It takes encodeURIComponent(url) string so it can decode these characters. | It takes encodeURI(url) string so it cannot decoded characters (, / ? : @ & = + $ #) |
Example |
decodeURIComponent(“%41”) It returns “A” decodeURIComponent(“%26”): It returns “&” |
decodeURI(“%41”): It returns “A” decodeURI(“%26”): It returns “%26” |