maia-util/es6/index_item_1st_doesnt_occur.js

Utility math and music functions supporting various applications by Music Artificial Intelligence Algorithms, Inc.

import array_equals from './array_equals'
export default function index_item_1st_doesnt_occur(arr,a){
  // Tom Collins 1/2/2015.
  // In
  // a Array, Boolean, Number, or String mandatory
  // Out Integer
  // Returns the index at which the given argument a first does not occur. It
  // is robust in the sense that it will match arguments consisting of arrays,
  // strings, and booleans as well as numbers. It will not match arbitrary
  // objects, however (see second example in testing).

  var typeofa = typeof a;
  var instanceofarraya = a instanceof Array;
  var idx = -1;
  var i = 0;
  while (i < arr.length)
  {
    if (!(typeof arr[i] == typeofa) ||
          (instanceofarraya && !(arr[i] instanceof Array))){
      idx = i;
      i = arr.length - 1;
    }
    else{
      if(instanceofarraya && arr[i] instanceof Array){
        if (!array_equals(arr[i],a)){
          idx = i;
          i = arr.length - 1;
        }
      }
      else{
        if (!(arr[i] == a)){
          idx = i;
          i = arr.length - 1;
        }
      }
    }
    i=i+1;
  }
  return idx;
}