Range.js：關于光標、選區以及范圍的操作。

定義一些輔助函數，以實現節點的定位

var getNodeBefore = function ( node, offset ) {
var children = node.childNodes;
// 
while ( offset && node.nodeType === ELEMENT_NODE ) {
    node = children[ offset - 1 ];
    children = node.childNodes;
    offset = children.length;
}
return node;
};

Range的增刪改查操作

// Returns the first block at least partially contained by the range,
// or null if no block is contained by the range.
var getStartBlockOfRange = function ( range, root ) {
    var container = range.startContainer,
        block;

    // If inline, get the containing block.
    if ( isInline( container ) ) {
        block = getPreviousBlock( container, root );
    } else if ( container !== root && isBlock( container ) ) {
        block = container;
    } else {
        block = getNodeBefore( container, range.startOffset );
        block = getNextBlock( block, root );
    }
    // Check the block actually intersects the range
    return block && isNodeContainedInRange( range, block, true ) ? block : null;
};

Node.js：關于節點的基礎定義，以及基本操作。

從各種角度，定義節點類型，如：inline&&block、葉子節點&&非葉子節點

定義查找指定節點的方法以及節點間的關系：

function getNearest ( node, root, tag, attributes ) {
    while ( node && node !== root ) {
        if ( hasTagAttributes( node, tag, attributes ) ) {
            return node;
        }
        node = node.parentNode;
    }
    return null;
}

定義節點以及之間的操作方法，如：split、merge等操作：

function _mergeInlines ( node, fakeRange ) {
    var children = node.childNodes,
        l = children.length,
        frags = [],
        child, prev, len;
    while ( l-- ) {
        child = children[l];
        prev = l && children[ l - 1 ];
        if ( l && isInline( child ) && areAlike( child, prev ) &&
                !leafNodeNames[ child.nodeName ] ) {
            if ( fakeRange.startContainer === child ) {
                fakeRange.startContainer = prev;
                fakeRange.startOffset += getLength( prev );
            }
            if ( fakeRange.endContainer === child ) {
                fakeRange.endContainer = prev;
                fakeRange.endOffset += getLength( prev );
            }
            if ( fakeRange.startContainer === node ) {
                if ( fakeRange.startOffset > l ) {
                    fakeRange.startOffset -= 1;
                }
                else if ( fakeRange.startOffset === l ) {
                    fakeRange.startContainer = prev;
                    fakeRange.startOffset = getLength( prev );
                }
            }
            if ( fakeRange.endContainer === node ) {
                if ( fakeRange.endOffset > l ) {
                    fakeRange.endOffset -= 1;
                }
                else if ( fakeRange.endOffset === l ) {
                    fakeRange.endContainer = prev;
                    fakeRange.endOffset = getLength( prev );
                }
            }
            detach( child );
            if ( child.nodeType === TEXT_NODE ) {
                prev.appendData( child.data );
            }
            else {
                frags.push( empty( child ) );
            }
        }
        else if ( child.nodeType === ELEMENT_NODE ) {
            len = frags.length;
            while ( len-- ) {
                child.appendChild( frags.pop() );
            }
            _mergeInlines( child, fakeRange );
        }
    }
}

TreeWakler.js：定義節點的遍歷模型，定義最基本的節點查找方法。

TreeWalker.prototype.previousNode = function () {
    var current = this.currentNode,
        root = this.root,
        nodeType = this.nodeType,
        filter = this.filter,
        node;
    while ( true ) {
        if ( current === root ) {
            return null;
        }
        node = current.previousSibling;
        if ( node ) {
            while ( current = node.lastChild ) {
                node = current;
            }
        } else {
            node = current.parentNode;
        }
        if ( !node ) {
            return null;
        }
        if ( ( typeToBitArray[ node.nodeType ] & nodeType ) &&
                filter( node ) ) {
            this.currentNode = node;
            return node;
        }
        current = node;
    }
};

Editor.js：編輯器構造函數的模型function Squire ( root, config ) { }。

編輯器構造函數

編輯器的參數操作函數

編輯器的原型方法（操作函數、自定義事件機制、光標以及選區的方法）

proto.getSelection = function () {
    var sel = getWindowSelection( this );
    var root = this._root;
    var selection, startContainer, endContainer, node;
    // If not focused, always rely on cached selection; another function may
    // have set it but the DOM is not modified until focus again
    if ( this._isFocused && sel && sel.rangeCount ) {
        selection  = sel.getRangeAt( 0 ).cloneRange();
        startContainer = selection.startContainer;
        endContainer = selection.endContainer;
        // FF can return the selection as being inside an . WTF?
        if ( startContainer && isLeaf( startContainer ) ) {
            selection.setStartBefore( startContainer );
        }
        if ( endContainer && isLeaf( endContainer ) ) {
            selection.setEndBefore( endContainer );
        }
    }
    if ( selection &&
            isOrContains( root, selection.commonAncestorContainer ) ) {
        this._lastSelection = selection;
    } else {
        selection = this._lastSelection;
        node = selection.commonAncestorContainer;
        // Check the editor is in the live document; if not, the range has
        // probably been rewritten by the browser and is bogus
        if ( !isOrContains( node.ownerDocument, node ) ) {
            selection = null;
        }
    }
    if ( !selection ) {
        selection = this._createRange( root.firstChild, 0 );
    }
    return selection;
};