Binaries.js

/*
Description:
Let us take a string composed of decimal digits: "10111213". We want to code this string as a string of 0 and 1 and after that be able to decode it.

We decompose the given string in its decimal digits 1 0 1 1 1 2 1 3 and we will code each.

Coding process to code a number n expressed in base 10:
a) Let k be the number of bits of n

b) Put k-1 times the digit 0 followed by the digit 1

c) Put number n in binary

d) Concat the result of b) and c)

So we code 0 as 10, 1 as 11 ... etc...

Repeating this process with the initial string

"10111213" becomes : "11101111110110110111" resulting of concatenation of 11 10 11 11 11 0110 11 0111 .

Task:
Given strng a string of digits representing a decimal number the function code(strng) should return the coding of strng as explained above.

Given a string strng resulting from the previous coding, decode it to get the corresponding decimal string.

Examples:
code("77338855") --> "001111001111011101110001100000011000001101001101"
code("77338")  --> "0011110011110111011100011000"
code("0011121314") --> "1010111111011011011111001100"

decode("001111001111011101110001100000011000001101001101") -> "77338855"
decode("0011110011110111011100011000") -> "77338"
decode("1010111111011011011111001100") -> "0011121314"
Note
Please could you ask before translating : some translations are already written.
*/
const ENC = ['10','11','0110','0111','001100','001101','001110','001111','00011000','00011001']

function code(strng) {
  return [...strng].map(c => ENC[c]).join('')
}
function decode(str) {
    pattern = new RegExp(ENC.join('|'), 'g')
    return str.replace(pattern, m => ENC.indexOf(m))
}