refactor: more compact table, -1% size for encoding-lite

Author: ChALkeR

fallback/single-byte.encodings.js

@@ -10,14 +10,16 @@ export const assertEncoding = (encoding) => {
   throw new RangeError('Unsupported encoding')
 }
 
+const f = 0xff_fd
+
 function getEncoding(encoding) {
   assertEncoding(encoding)
   if (encoding === xUserDefined) {
     return Array.from({ length: 128 }, (_, i) => 0xf7_80 + i)
   }
 
   let prev = 127
-  return encodings[encoding].map((x) => (prev += x)) // eslint-disable-line no-return-assign
+  return encodings[encoding].map((x) => x === f ? x : (prev += x)) // eslint-disable-line no-return-assign
 }
 
 const mappers = new Map()