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decodeURIComponent()

Baseline

20157

decodeURIComponent() encodeURIComponent() URI (Uniform Resource Identifier; ) 

function containsEncodedComponents(x) {
  // ie ?,=,&,/ etc
  return decodeURI(x) !== decodeURIComponent(x);
}

console.log(containsEncodedComponents("%3Fx%3Dtest")); // ?x=test
// : true

console.log(containsEncodedComponents("%D1%88%D0%B5%D0%BB%D0%BB%D1%8B")); // 
// : false

js
decodeURIComponent(encodedURI)

encodedURI

URI

(URI)

URIError

encodedURI 2 16 % UTF-8

decodeURIComponent()

decodeURIComponent() decodeURI() -.!~*'() encodeURIComponent

URL

js
decodeURIComponent("JavaScript_%D1%88%D0%B5%D0%BB%D0%BB%D1%8B");
// "JavaScript_"

js
try {
  const a = decodeURIComponent("%E0%A4%A");
} catch (e) {
  console.error(e);
}

// URIError: malformed URI sequence

URL

decodeURIComponent() URL

js
function decodeQueryParam(p) {
  return decodeURIComponent(p.replace(/\+/g, " "));
}

decodeQueryParam("search+query%20%28correct%29");
// 'search query (correct)'

ECMAScript 2027 LanguageSpecification
# sec-decodeuricomponent-encodeduricomponent

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