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decodeURIComponent()
Baseline
Widely available
This feature is well established and works across many devices and browser versions. It’s been available across browsers since July 2015.
The decodeURIComponent() function decodes a Uniform Resource Identifier (URI) component previously created by encodeURIComponent() or by a similar routine.
function containsEncodedComponents(x) {
// ie ?,=,&,/ etc
return decodeURI(x) !== decodeURIComponent(x);
}
console.log(containsEncodedComponents("%3Fx%3Dtest")); // ?x=test
// Expected output: true
console.log(containsEncodedComponents("%D1%88%D0%B5%D0%BB%D0%BB%D1%8B")); // шеллы
// Expected output: false
js
decodeURIComponent(encodedURI)
encodedURI-
An encoded component of a Uniform Resource Identifier.
A new string representing the decoded version of the given encoded Uniform Resource Identifier (URI) component.
URIError-
Thrown if encodedURI contains a % not followed by two hexadecimal digits, or if the escape sequence does not encode a valid UTF-8 character.
decodeURIComponent() is a function property of the global object.
decodeURIComponent() uses the same decoding algorithm as described in decodeURI(). It decodes all escape sequences, including those that are not created by encodeURIComponent, like -.!~*'().
js
decodeURIComponent("JavaScript_%D1%88%D0%B5%D0%BB%D0%BB%D1%8B");
// "JavaScript_шеллы"
js
try {
const a = decodeURIComponent("%E0%A4%A");
} catch (e) {
console.error(e);
}
// URIError: malformed URI sequence
decodeURIComponent() cannot be used directly to parse query parameters from a URL. It needs a bit of preparation.
js
function decodeQueryParam(p) {
return decodeURIComponent(p.replace(/\+/g, " "));
}
decodeQueryParam("search+query%20%28correct%29");
// 'search query (correct)'