Characters

Q: A string is "a series of characters"... but what is a character?

A: a character is a number (or character code) that stands for a symbol.

(Some characters stand for unprintable symbols like newline or tab or bell.)

ASCII and ye shall receive-ski

ASCII Table

ASCII only goes from 0 to 127
Unicode is the same as ASCII for values from 0 and 127
- but Unicode goes a lot higher
Currently more than 130,000 characters, including symbols for
- 139 modern and historic scripts
- accents and other diacritics
- various mathematical ∞, currency £, and cultural ☮ symbols
- emoji 😂

JavaScript strings are Unicode

That means you can use emoji in your JavaScript programs!

Like this:

"😂".repeat(20)

(sadly this doesn't work in Windows PowerShell, but it does work in Atom+node, like this:)

  response.setHeader('content-type', 'text/html');
  response.write('<meta charset="UTF-8">')
  response.write("😂".repeat(20));
  response.end();

UTF-32 is a fixed-width encoding for Unicode
- every character is 32 bits long
UTF-8 is a variable-width encoding for Unicode
- all ASCII characters are one byte long (8 bits)
- other characters are up to four bytes long (32 bits)
- used for text files
UTF-16 is a variable-width encoding for Unicode
- every character is either 16 or 32 bits long
- used by JavaScript at runtime

[TODO: diagrams]