Cannot read property 'heading' of null - node.js

Question

My problem is I got an unexpected error at the browser end that says Cannot read property 'heading' of null
also marks this error at the client page file like about.ejs and showing; in the snap attached
I have provided all the required codes related to this. I reviewed multiple times to find for what or to where the actual errror originated but did not able to fix it.
codes of about.ejs
<%-include('./partials/header')%>
<div class="container-fluid">
<h1>About Section</h1>
<div class="card shadow mb-4">
<div class="card-header">
<form action="/admin/portfolio/create" method="post">
<button type="submit" class="btn btn-success">Edit About Page</button>
</form>
</div>
<div class="card-header py-3">
<h6 class="m-0 font-weight-bold text-primary">About Area</h6>
</div>
<div class="card-body">
<div class="table-responsive">
<form action="/admin/about" method="post" >
<div class="form-group">
<label for="exampleFormControlInput1">Headings:</label>
<input class="form-control" type="text" name="heading" id="exampleFormControlInput1" value="<%=about.heading%>" >
</div>
<div class="form-group">
<label for="exampleFormControlInput2">Sub-Headings:</label>
<input class="form-control" type="text" name="subheading" id="exampleFormControlInput2" value="<%=about.subheading%>" >
</div>
<div class="form-group">
<textarea id="editor1" name="content" rows="10" cols="80"><%=about.content%></textarea>
</div>
<button type="submit" class="btn btn-primary">Save & Update</button>
</form>
</div>
</div>
</div>
<%-include('./partials/footer')%>
here is my router.js file
router.get('/admin/about',serverController.isAuthenticated,serverController.about)
router.post('/admin/about',serverController.isAuthenticated,serverController.about_post)
This is also my controller file
exports.about = async function(req,res){
res.render('server/about', {
about : await aboutCollection.findOne()
})
}
exports.about_post = function(req,res){
let about = new About(req.body)
about.create().then(async()=>{
res.redirect('/admin/about')
}).catch(()=>{
res.send('404')
})
}
and finally this all about my model of about page
const aboutCollection = require('../db').db().collection('about')
const objectId = require('mongodb').ObjectID
const About = function(about){
this.about = about
}
About.prototype.create = function(){
return new Promise(async(resolve,reject)=>{
await aboutCollection.updateOne({}, {$set :
{
heading : this.about.heading,
subheading : this.about.subheading,
content : this.about.content
}
})
resolve()
})
}
module.exports = About

Answer 1

it's because about sent value of none at the ejs tag i mean
<%= about.heading%>
Do,
exports.about = async function(req,res){
res.render('server/about', {
about : await aboutCollection.find().toArray()
})
}
Instead of,
exports.about = async function(req,res){
res.render('server/about', {
about : await aboutCollection.findOne()
})
}
In my case, I did this; after trying then see error has gone.