check_input.hhs

/**
 * @author Jing Stone
 * @param input input must be a JS array
 * @return true if input is 2d matrix of 1d list
 *  check the input array if it is a matrix or a vector(1d list)
 *  
 */

function check_input(input)
{
  if(!Array.isArray(input)) return false;

  let inputLength = input.length;
  // empty array [] 
  if(inputLength === 0) return true;
  // check if it is a vector
  if(typeof input[0] === 'number')
  {
    for(let i = 0; i < inputLength; i++)
    {
      if(!(typeof input[i] === 'number'))
      {
        return false;
      }
    }
  }
  // check if it is a matrix
  else
  {
    let col = input.length;
    let row = input[0].length;
    // not allowed [[]]
    if(row === 0) return false;
    // a matrix should have the same length of column and row
    // while the column can not equal to row
    for(let i = 0; i < col; i++)
    {
      if(!Array.isArray(input[i])) return false;
      if(!input[i].length === row) return false;
      for(let j = 0; j < row; j++)
      {
        if(!(typeof input[i][j] === 'number'))
        {
          return false;
        }
      }
    }
  }
  return true;
}