jasmine-where.js
function shouldNotHaveDuplicateLabels(row) {
    for (var label, visited = {}, j = 0; j < row.length; j += 1) {
    
      label = row[j];

      if (visited[label]) {
        throw new Error('where-data table contains duplicate label \'' + label +
                        '\' in [' + row.join(', ') + ']');
      }
      
      visited[label] = 1;
    }
  }
function shouldNotHaveDuplicateLabels(row) {
    for (var label, visited = {}, j = 0; j < row.length; j += 1) {
    
      label = row[j];

      if (visited[label]) {
        throw new Error('where-data table contains duplicate label \'' + label +
                        '\' in [' + row.join(', ') + ']');
      }
      
      visited[label] = 1;
    }
  }
/*
@private
@method shouldNotHaveDuplicateLabels() checks that row of data contains no duplicated
data values - mainly used for checking column headers (a,b,c vs. a,b,b).
@param row array of values.