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Unicoding emoji
// http://www.2ality.com/2013/09/javascript-unicode.html
function toUTF16(codePoint) {
var TEN_BITS = parseInt('1111111111', 2);
function u(codeUnit) {
return '\\u'+codeUnit.toString(16).toUpperCase();
}
if (codePoint <= 0xFFFF) {
return u(codePoint);
}
codePoint -= 0x10000;
// Shift right to get to most significant 10 bits
var leadSurrogate = 0xD800 + (codePoint >> 10);
// Mask to get least significant 10 bits
var tailSurrogate = 0xDC00 + (codePoint & TEN_BITS);
return u(leadSurrogate) + u(tailSurrogate);
}
// using codePointAt, it's easy to go from emoji
// to decimal and back.
// Emoji to decimal representation
"😀".codePointAt(0)
>128512
// Decimal to emoji
String.fromCodePoint(128512)
>"😀"
// going from emoji to hexadecimal is a little
// bit trickier. To convert from decimal to hexadecimal,
// we can use toUTF16.
// Decimal to hexadecimal
toUTF16(128512)
> "\uD83D\uDE00"
// Hexadecimal to emoji
"\uD83D\uDE00"
> "😀"
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