Add numberHelper support for 'e' notation

Javascript's parseFloat supports this natively, so we can handle it if
all else fails.

Test Plan:
- As a teacher, create a quiz with a numeric question
- Enter `3e4` as an answer
- On blur, see it replaced with `3000`

Closes QO-512

Change-Id: Ia7c7e196ed0baa302fc6b6f79eda611955f75d2b
Reviewed-on: https://gerrit.instructure.com/206463
Tested-by: Jenkins
Product-Review: Kevin Dougherty III <jdougherty@instructure.com>
Reviewed-by: Connor Williams <cowilliams@instructure.com>
QA-Review: David Tan <dtan@instructure.com>

app/jsx/shared/helpers/numberHelper.js

@@ -39,6 +39,17 @@ import I18n from 'i18nObj'
         num = helper._parseNumber(input)
       }
 
+      // final fallback to old parseFloat - this allows us to still support scientific 'e' notation
+      if (input.toString().indexOf('e') > -1 && isNaN(num)) {
+        num = parseFloat(input)
+
+        // Over 'e20' these don't produce usable numbers,
+        // so we just have to cap it for simplicity's sake...
+        if(num.toString().indexOf('e') > -1) {
+          return NaN
+        }
+      }
+
       return num
     },
 

spec/javascripts/jsx/shared/helpers/numberHelperSpec.js

@@ -93,6 +93,11 @@ test('returns input if already a number', () => {
   equal(numberHelper.parse(input), input)
 })
 
+test('supports e notation', () => {
+  numberHelper._parseNumber.restore()
+  equal(numberHelper.parse('3e2'), 300)
+})
+
 test('parses toString value of objects', () => {
   numberHelper._parseNumber.restore()
   const obj = {toString: () => `2${separator}3`}