encodeURIComponent algorithm source code

I am developing an application in titanium using Javascript. I need an open source implementation of encodeURIComponent in Javascript.

Can anybody guide me or show me some implementation?

The specification for this function is in 15.1.3.4.

Modern versions (2018) of V8 implement it in C++. See src/uri.h:

// ES6 section 18.2.6.5 encodeURIComponenet (uriComponent)
static MaybeHandle<String> EncodeUriComponent(Isolate* isolate,
                                              Handle<String> component) {

which calls into Encode defined in uri.cc.

Older versions of V8 implemented it in JavaScript and distributed under the BSD license. See line 359 of src/uri.js.

// ECMA-262 - 15.1.3.4
function URIEncodeComponent(component) {
  var unescapePredicate = function(cc) {
    if (isAlphaNumeric(cc)) return true;
    // !
    if (cc == 33) return true;
    // '()*
    if (39 <= cc && cc <= 42) return true;
    // -.
    if (45 <= cc && cc <= 46) return true;
    // _
    if (cc == 95) return true;
    // ~
    if (cc == 126) return true;

    return false;
  };

  var string = ToString(component);
  return Encode(string, unescapePredicate);
}

It's not called encodeURIComponent there, but this code in the same file, esablishes the mapping:

InstallFunctions(global, DONT_ENUM, $Array(
    "escape", URIEscape,
    "unescape", URIUnescape,
    "decodeURI", URIDecode,
    "decodeURIComponent", URIDecodeComponent,
    "encodeURI", URIEncode,
    "encodeURIComponent", URIEncodeComponent
  ));