Converting text to Unicode in javascript

Question

I have the following:

function showUnicode()
{
  var text = prompt( 'Enter the wanted text', 'Unicode' ),
      unicode = 0,
      ntext,
      temp,
      i = 0
  ;

  // got the text now transform it in unicode
  for(i; i < text.length; i++)
  {
    unicode += text.charCodeAt(i)

  }

  // now do an alert
  alert( 'Here is the unicode:\n' + unicode + '\nof:\n' + text )

}

Thanks for the idea to initialize unicode but now unicode variable gets the Unicode of the last character, why does it?

unicode is not initialized, so it is undefined. In the first iteration, you are basically doing undefined + someNumber and undefined is converted to NaN. — Felix Kling
– Felix Kling, Commented Jan 18, 2012 at 18:57
charCodeAt returns an integer repsenting the unicode codepoint value. If you add them up as you are, you'll be getting back the equivalent of "1+2+3=6", not "123". — Marc B
– Marc B, Commented Jan 18, 2012 at 18:58
well now i initialized unicode to 0 but it shows just the unicode of the last character — Andrew
– Andrew, Commented Jan 18, 2012 at 19:08

Mathias Bynens · Accepted Answer · 2012-02-02 08:45:42Z

4

JavaScript uses UCS-2 internally.

This means that supplementary Unicode symbols are exposed as two separate code units (the surrogate halves). For example, '𝌆'.length == 2, even though it’s only one Unicode character.

Because of this, if you want to get the Unicode code point for every character in a string, you’ll need to convert the UCS-2 string into an array of UTF-16 code points (where each surrogate pair forms a single code point). You could use Punycode.js’s utility functions for this:

punycode.ucs2.decode('abc'); // [97, 98, 99]
punycode.ucs2.decode('𝌆'); // [119558]

answered Feb 2, 2012 at 8:45

Mathias Bynens

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Comments

James M · Accepted Answer · 2012-01-18 18:56:30Z

2

You should initialize the unicode variable to something, or you're adding the char codes to undefined.

answered Jan 18, 2012 at 18:56

James M

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Comments

Diodeus - James MacFarlane · Accepted Answer · 2012-01-18 18:56:23Z

1

NaN = Not a Number

You need to initialize "unicode" as a numeric type:

var unicode = 0

answered Jan 18, 2012 at 18:56

Diodeus - James MacFarlane

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