Function indexOfCharCode

indexOfCharCode(
    source: string,
    code: number,
    start?: number,
    end?: number,
): number
Returns first position of the given character code, or -1 if not found.
Parameters
- source: string
  Source string
- code: number
  Code to seek
- start: number = 0
  Start index, 0 by default
- end: number = ...
  End index (inclusive), source.length-1 by default
Returns number
Found position, or -1 if not found