114. implement BigInt multiplication

JavaScript

medium  - accepted / - tried

This is a follow-up on 76. implement BigInt addition with sign.

You are asked to create a function that multiplies two big integers in string.

multiply(
  '1123456787654323456789', 
  '1234567887654323456'
)
// '1386983673205309924427166592431045142784'

Think about the edge cases.

(9)