error when hitting GET route but data shows up - node.js

Question

when hitting a get route, I get the data I am expecting but it looks like my route is hit TWICE: once with data, and another time with no info supplied.
if I navigate to a URL: https://www.something.com/events/XYZ then I get all the data and the page is populated properly. The page never seems to finish loading unless I click on the "X" in the browser.
app.get("/events/:id", function(req, res){
Event.findById(req.params.id, function (err, foundEvent){
if(err){
console.log("beginning error");
console.log(err);
console.log("found this event: " + foundEvent);
console.log("ending error");
}else {
console.log("now entering normal loop");
console.log(foundEvent);
res.render("showevent", {event: foundEvent});
}
})
});
When I type in a URL (copy/paste), I get the following (lengthy, sorry, not sure which part may be relevant) console.log:
now entering normal loop
{ _id: 5cf30944e75f2679f77287a2,
name: 'Memorial Day 2019',
date: 2019-06-01T23:24:52.063Z,
story: 'Memorial Day parade and Ceremony',
posts: [ { link: [Array], image: [], _id: 5cf30944e75f2679f77287a3 } ],
__v: 0 }
beginning error
{ CastError: Cast to ObjectId failed for value "main.js" at path "_id" for model "Event"
at new CastError (/home/scott/cchistory/cchistory/node_modules/mongoose/lib/error/cast.js:29:11)
at ObjectId.cast (/home/scott/cchistory/cchistory/node_modules/mongoose/lib/schema/objectid.js:242:11)
at ObjectId.SchemaType.applySetters (/home/scott/cchistory/cchistory/node_modules/mongoose/lib/schematype.js:892:12)
at ObjectId.SchemaType._castForQuery (/home/scott/cchistory/cchistory/node_modules/mongoose/lib/schematype.js:1304:15)
at ObjectId.SchemaType.castForQuery (/home/scott/cchistory/cchistory/node_modules/mongoose/lib/schematype.js:1294:15)
at ObjectId.SchemaType.castForQueryWrapper (/home/scott/cchistory/cchistory/node_modules/mongoose/lib/schematype.js:1273:15)
at cast (/home/scott/cchistory/cchistory/node_modules/mongoose/lib/cast.js:307:32)
at model.Query.Query.cast (/home/scott/cchistory/cchistory/node_modules/mongoose/lib/query.js:4529:12)
at model.Query.Query._castConditions (/home/scott/cchistory/cchistory/node_modules/mongoose/lib/query.js:1762:10)
at model.Query.<anonymous> (/home/scott/cchistory/cchistory/node_modules/mongoose/lib/query.js:2015:8)
at model.Query._wrappedThunk [as _findOne] (/home/scott/cchistory/cchistory/node_modules/mongoose/lib/helpers/query/wrapThunk.js:16:8)
at process.nextTick (/home/scott/cchistory/cchistory/node_modules/kareem/index.js:369:33)
at _combinedTickCallback (internal/process/next_tick.js:131:7)
at process._tickCallback (internal/process/next_tick.js:180:9)
message: 'Cast to ObjectId failed for value "main.js" at path "_id" for model "Event"',
name: 'CastError',
stringValue: '"main.js"',
kind: 'ObjectId',
value: 'main.js',
path: '_id',
reason: undefined,
model:
{ [Function: model]
hooks: Kareem { _pres: [Object], _posts: [Object] },
base:
Mongoose {
connections: [Array],
models: [Object],
modelSchemas: [Object],
options: [Object],
_pluralize: [Function: pluralize],
Schema: [Object],
model: [Function],
plugins: [Array] },
modelName: 'Event',
model: [Function: model],
db:
NativeConnection {
base: [Object],
collections: [Object],
models: [Object],
config: [Object],
replica: false,
options: null,
otherDbs: [],
relatedDbs: {},
states: [Object],
_readyState: 1,
_closeCalled: false,
_hasOpened: true,
plugins: [],
'$internalEmitter': [Object],
_listening: false,
_connectionOptions: [Object],
name: 'historydb',
host: 'localhost',
port: 27017,
user: undefined,
pass: undefined,
client: [Object],
'$initialConnection': [Object],
db: [Object] },
discriminators: undefined,
events:
EventEmitter {
domain: null,
_events: {},
_eventsCount: 0,
_maxListeners: undefined },
'$appliedMethods': true,
'$appliedHooks': true,
_middleware: Kareem { _pres: [Object], _posts: [Object] },
'$__insertMany': [Function],
schema:
Schema {
obj: [Object],
paths: [Object],
aliases: {},
subpaths: {},
virtuals: [Object],
singleNestedPaths: {},
nested: {},
inherits: {},
callQueue: [],
_indexes: [],
methods: {},
methodOptions: {},
statics: {},
tree: [Object],
query: {},
childSchemas: [Array],
plugins: [Array],
'$id': 6,
s: [Object],
_userProvidedOptions: {},
options: [Object],
'$globalPluginsApplied': true,
_requiredpaths: [] },
collection:
NativeCollection {
collection: [Object],
Promise: [Function: Promise],
opts: [Object],
name: 'events',
collectionName: 'events',
conn: [Object],
queue: [],
buffer: false,
emitter: [Object] },
Query: { [Function] base: [Object] },
'$init': Promise { [Circular] },
'$caught': true,
[Symbol(mongoose#Model)]: true } }
found this event: undefined
ending error

Answer 1

The "double whammy" was caused by a search bar that was on the page. With not info entered, it would hit the route with no info and cause the error.
I am moving the search function to a dedicated page for simplicity.
Thanks for the help folks!