Merge pull request #13 from pat310/12MaximumCallStack

throwing error if pivot category does not exist

logic.js

@@ -122,8 +122,20 @@ function accumulator(arr, accCat, accType, accValue){
   }, accValue || 0);
 }
 
+function checkPivotCategories(actualCats, selectedCats){
+  var errMessage = [];
+  selectedCats.forEach(selectedCat =>{
+    if(actualCats.indexOf(selectedCat) === -1) errMessage.push(selectedCat); 
+  });
+  if(errMessage.length) throw new Error(`Check that these selected pivot categories exist: ${errMessage.join(',')}`);
+}
+
 function tableCreator(data, rows = [], cols = [], accCatOrCB, accTypeOrInitVal, rowHeader){
   data = fixDataFormat(data);
+  if(!data.length) return [];
+  checkPivotCategories(Object.keys(data[0]), rows);
+  checkPivotCategories(Object.keys(data[0]), cols);
+
   if(typeof rowHeader === 'undefined') rowHeader = typeof accCatOrCB !== 'function' ? `${accTypeOrInitVal} ${accCatOrCB}` : 'Custom Agg';
 
   const columnData = createColumnHeaders(data, cols, rowHeader);
@@ -190,5 +202,6 @@ module.exports = {
   groupByCategory,
   groupByCategories,
   createColumnHeaders,
-  accumulator
+  accumulator,
+  checkPivotCategories
 };

test.js

@@ -6,7 +6,8 @@ const {
   groupByCategories,
   createColumnHeaders,
   accumulator,
-  tableCreator
+  tableCreator,
+  checkPivotCategories
 } = require('./logic');
 
 const chai = require('chai');
@@ -253,6 +254,19 @@ describe('accumulator', function(){
   });
 });
 
+describe('checkPivotCategories', function(){
+  var actualCategories = ['pig', 'fish', 'dog'];
+
+  it('should return undefined if pivot category exists', function(){
+    expect(checkPivotCategories(actualCategories, ['dog'])).to.be.undefined;
+  });
+
+  it('should throw an error if pivot category does not exist', function(){
+    var errorFunc = checkPivotCategories.bind(null, actualCategories, ['cat']);
+    expect(errorFunc).to.throw(Error);
+  });
+});
+
 describe('tableCreator', function(){
   it('should take an array of objects, an array of row categories, an array of column categories, an accumulation category, and an accumulation type and return an object containing the table and data comprising the table', function(){
     var tableResults = tableCreator(data, ['gender'], ['borough'], 'age', 'count');