How do I assemble a Unicode string?

If I do this:

alert('\u0444')

I get a 'CYRILLIC SMALL LETTER EF' (ф).

But if I do this:

alert('\u' + '0444')

I don't -- I get a literal u, like this: u0444.

I'm interested in generating an array containing various entire Unicode blocks, so I need to build these strings programmatically.

How can I do that?

Like this:

String.fromCharCode('444')

Except... not exactly. Because .fromCharCode() is expecting a decimal number. So, we need to convert to decimal first:

String.fromCharCode(parseInt(444,16))