Image Node Type – contenteditable.lab

Schema Definition

Schema definition for the Image node type:

{
  image: {
    inline: true,
    attrs: {
      src: { default: '' },
      alt: { default: '' },
      title: { default: null },
      width: { default: null },
      height: { default: null }
    }
  }
}

Model Representation

Example model representation:

{
  type: 'image',
  attrs: {
    src: 'https://example.com/image.jpg',
    alt: 'Description',
    width: 800,
    height: 600
  }
}

HTML Serialization

Converting model to HTML:

function serializeImage(node) {
  const attrs = {};
  if (node.attrs.src) attrs.src = escapeHtml(node.attrs.src);
  if (node.attrs.alt) attrs.alt = escapeHtml(node.attrs.alt);
  if (node.attrs.title) attrs.title = escapeHtml(node.attrs.title);
  if (node.attrs.width) attrs.width = node.attrs.width;
  if (node.attrs.height) attrs.height = node.attrs.height;
  return '<img' + serializeAttrs(attrs) + '>';
}

HTML Deserialization

Parsing HTML to model:

function parseImage(domNode) {
  return {
    type: 'image',
    attrs: {
      src: domNode.getAttribute('src') || '',
      alt: domNode.getAttribute('alt') || '',
      title: domNode.getAttribute('title') || null,
      width: parseInt(domNode.getAttribute('width')) || null,
      height: parseInt(domNode.getAttribute('height')) || null
    }
  };
}

View Integration

View Integration Notes: Pay special attention to contenteditable behavior, selection handling, and event management when implementing this node type in your view layer.

View integration code:

// Rendering image
const img = document.createElement('img');
img.src = node.attrs.src;
img.alt = node.attrs.alt || '';
if (node.attrs.title) img.title = node.attrs.title;
if (node.attrs.width) img.width = node.attrs.width;
if (node.attrs.height) img.height = node.attrs.height;
img.contentEditable = 'false'; // Images are typically not editable

// Image upload handler
function handleImageUpload(file) {
  const reader = new FileReader();
  reader.onload = (e) => {
    insertNode({
      type: 'image',
      attrs: {
        src: e.target.result,
        alt: file.name
      }
    });
  };
  reader.readAsDataURL(file);
}

Common Issues

Common Pitfalls: These are issues frequently encountered when implementing this node type. Review carefully before implementation.

Common issues and solutions:

// Issue: Image loading errors
// Solution: Handle broken images
img.onerror = function() {
  this.src = 'placeholder.jpg';
  this.alt = 'Image failed to load';
};

// Issue: Image resizing
// Solution: Maintain aspect ratio
function resizeImage(img, maxWidth, maxHeight) {
  const ratio = Math.min(maxWidth / img.width, maxHeight / img.height);
  img.width = img.width * ratio;
  img.height = img.height * ratio;
}

// Issue: Image selection
// Solution: Handle image selection in contenteditable
function selectImage(img) {
  const range = document.createRange();
  range.selectNode(img);
  const selection = window.getSelection();
  selection.removeAllRanges();
  selection.addRange(range);
}

Implementation

Complete implementation example:

class ImageNode {
  constructor(attrs) {
    this.type = 'image';
    this.attrs = {
      src: attrs?.src || '',
      alt: attrs?.alt || '',
      title: attrs?.title || null,
      width: attrs?.width || null,
      height: attrs?.height || null
    };
  }
  
  toDOM() {
    const img = document.createElement('img');
    Object.assign(img, this.attrs);
    return img;
  }
  
  static fromDOM(domNode) {
    return new ImageNode({
      src: domNode.getAttribute('src') || '',
      alt: domNode.getAttribute('alt') || '',
      title: domNode.getAttribute('title') || null,
      width: parseInt(domNode.getAttribute('width')) || null,
      height: parseInt(domNode.getAttribute('height')) || null
    });
  }
}