Project Image Embeds

The Subdocument Model

We previously stored project tags as embedded sub-documents. Let’s do the same for projectImages.

Each project can have zero, one, or multiple projectImages, so we need an array.

Fig 1: Document Structure vs Physical Storage

The Project Image Schema

In Mongoose, arrays of Objects are called Subdocuments. We can create a standalone schema specifically for the visual shape of this embedded data.

data/projects.js

const mongoose = require('mongoose');

// A sub-schema explicitly designed to shape items inside an array
const projectImageSchema = new mongoose.Schema(
  {
    originalName: String,
    filename: String,
    altText: String, // Optional descriptive text
    caption: String, // Optional display string
    isFeatured: { type: Boolean, default: false },
    uploadedAt: { type: Date, default: Date.now },
  },
  { _id: false } // Avoid MongoDB generating unique nested IDs inside this embedded array unless specifically needed!
);

const projectSchema = new mongoose.Schema({
  // ... other fields

  // Array of strictly shaped subdocuments!
  projectImages: [projectImageSchema],
});

Professor Solo

Why use an embedded projectImageSchema instead of a separate referenced media collection? A project’s projectImages fundamentally exist to support that specific project. They operate in the context of the parent project. Furthermore, fetching a Project instantly gives you all its image metadata without expensive populate() joins.

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⏭ Next: Install Multer

Now that our data model is ready, let’s meet multer, the middleware responsible for actually catching these binary file uploads.