// Modified from https://github.com/hamflx/prosemirror-diff/blob/master/src/diff.js import { diff_match_patch } from 'diff-match-patch'; import { Fragment, Node } from 'prosemirror-model'; export const DiffType = { Unchanged: 0, Deleted: -1, Inserted: 1, }; export const patchDocumentNode = (schema, oldNode, newNode) => { assertNodeTypeEqual(oldNode, newNode); const finalLeftChildren = []; const finalRightChildren = []; const oldChildren = normalizeNodeContent(oldNode); const newChildren = normalizeNodeContent(newNode); const oldChildLen = oldChildren.length; const newChildLen = newChildren.length; const minChildLen = Math.min(oldChildLen, newChildLen); let left = 0; let right = 0; for (; left < minChildLen; left++) { const oldChild = oldChildren[left]; const newChild = newChildren[left]; if (!isNodeEqual(oldChild, newChild)) { break; } finalLeftChildren.push(...ensureArray(oldChild)); } for (; right + left + 1 < minChildLen; right++) { const oldChild = oldChildren[oldChildLen - right - 1]; const newChild = newChildren[newChildLen - right - 1]; if (!isNodeEqual(oldChild, newChild)) { break; } finalRightChildren.unshift(...ensureArray(oldChild)); } const diffOldChildren = oldChildren.slice(left, oldChildLen - right); const diffNewChildren = newChildren.slice(left, newChildLen - right); if (diffOldChildren.length && diffNewChildren.length) { const matchedNodes = matchNodes( schema, diffOldChildren, diffNewChildren, ).sort((a, b) => b.count - a.count); const bestMatch = matchedNodes[0]; if (bestMatch) { const { oldStartIndex, newStartIndex, oldEndIndex, newEndIndex } = bestMatch; const oldBeforeMatchChildren = diffOldChildren.slice(0, oldStartIndex); const newBeforeMatchChildren = diffNewChildren.slice(0, newStartIndex); finalLeftChildren.push( ...patchRemainNodes( schema, oldBeforeMatchChildren, newBeforeMatchChildren, ), ); finalLeftChildren.push( ...diffOldChildren.slice(oldStartIndex, oldEndIndex), ); const oldAfterMatchChildren = diffOldChildren.slice(oldEndIndex); const newAfterMatchChildren = diffNewChildren.slice(newEndIndex); finalRightChildren.unshift( ...patchRemainNodes( schema, oldAfterMatchChildren, newAfterMatchChildren, ), ); } else { finalLeftChildren.push( ...patchRemainNodes(schema, diffOldChildren, diffNewChildren), ); } } else { finalLeftChildren.push( ...patchRemainNodes(schema, diffOldChildren, diffNewChildren), ); } return createNewNode(oldNode, [...finalLeftChildren, ...finalRightChildren]); }; const matchNodes = (schema, oldChildren, newChildren) => { const matches = []; for ( let oldStartIndex = 0; oldStartIndex < oldChildren.length; oldStartIndex++ ) { const oldStartNode = oldChildren[oldStartIndex]; const newStartIndex = findMatchNode(newChildren, oldStartNode); if (newStartIndex !== -1) { let oldEndIndex = oldStartIndex + 1; let newEndIndex = newStartIndex + 1; for ( ; oldEndIndex < oldChildren.length && newEndIndex < newChildren.length; oldEndIndex++, newEndIndex++ ) { const oldEndNode = oldChildren[oldEndIndex]; if (!isNodeEqual(newChildren[newEndIndex], oldEndNode)) { break; } } matches.push({ oldStartIndex, newStartIndex, oldEndIndex, newEndIndex, count: newEndIndex - newStartIndex, }); } } return matches; }; const findMatchNode = (children, node, startIndex = 0) => { for (let i = startIndex; i < children.length; i++) { if (isNodeEqual(children[i], node)) { return i; } } return -1; }; const patchRemainNodes = (schema, oldChildren, newChildren) => { const finalLeftChildren = []; const finalRightChildren = []; const oldChildLen = oldChildren.length; const newChildLen = newChildren.length; let left = 0; let right = 0; while (oldChildLen - left - right > 0 && newChildLen - left - right > 0) { const leftOldNode = oldChildren[left]; const leftNewNode = newChildren[left]; const rightOldNode = oldChildren[oldChildLen - right - 1]; const rightNewNode = newChildren[newChildLen - right - 1]; let updateLeft = !isTextNode(leftOldNode) && matchNodeType(leftOldNode, leftNewNode); let updateRight = !isTextNode(rightOldNode) && matchNodeType(rightOldNode, rightNewNode); if (Array.isArray(leftOldNode) && Array.isArray(leftNewNode)) { finalLeftChildren.push( ...patchTextNodes(schema, leftOldNode, leftNewNode), ); left += 1; continue; } if (updateLeft && updateRight) { const equalityLeft = computeChildEqualityFactor(leftOldNode, leftNewNode); const equalityRight = computeChildEqualityFactor( rightOldNode, rightNewNode, ); if (equalityLeft < equalityRight) { updateLeft = false; } else { updateRight = false; } } if (updateLeft) { finalLeftChildren.push( patchDocumentNode(schema, leftOldNode, leftNewNode), ); left += 1; } else if (updateRight) { finalRightChildren.unshift( patchDocumentNode(schema, rightOldNode, rightNewNode), ); right += 1; } else { // Delete and insert finalLeftChildren.push( createDiffNode(schema, leftOldNode, DiffType.Deleted), ); finalLeftChildren.push( createDiffNode(schema, leftNewNode, DiffType.Inserted), ); left += 1; } } const deleteNodeLen = oldChildLen - left - right; const insertNodeLen = newChildLen - left - right; if (deleteNodeLen) { finalLeftChildren.push( ...oldChildren .slice(left, left + deleteNodeLen) .flat() .map((node) => createDiffNode(schema, node, DiffType.Deleted)), ); } if (insertNodeLen) { finalRightChildren.unshift( ...newChildren .slice(left, left + insertNodeLen) .flat() .map((node) => createDiffNode(schema, node, DiffType.Inserted)), ); } return [...finalLeftChildren, ...finalRightChildren]; }; // Updated function to perform sentence-level diffs export const patchTextNodes = (schema, oldNode, newNode) => { const dmp = new diff_match_patch(); // Concatenate the text from the text nodes const oldText = oldNode.map((n) => getNodeText(n)).join(''); const newText = newNode.map((n) => getNodeText(n)).join(''); // Tokenize the text into sentences const oldSentences = tokenizeSentences(oldText); const newSentences = tokenizeSentences(newText); // Map sentences to unique characters const { chars1, chars2, lineArray } = sentencesToChars( oldSentences, newSentences, ); // Perform the diff let diffs = dmp.diff_main(chars1, chars2, false); // Convert back to sentences diffs = diffs.map(([type, text]) => { const sentences = text .split('') .map((char) => lineArray[char.charCodeAt(0)]); return [type, sentences]; }); // Map diffs to nodes const res = diffs.flatMap(([type, sentences]) => { return sentences.map((sentence) => { const node = createTextNode( schema, sentence, type !== DiffType.Unchanged ? [createDiffMark(schema, type)] : [], ); return node; }); }); return res; }; // Function to tokenize text into sentences const tokenizeSentences = (text) => { return text.match(/[^.!?]+[.!?]*\s*/g) || []; }; // Function to map sentences to unique characters const sentencesToChars = (oldSentences, newSentences) => { const lineArray = []; const lineHash = {}; let lineStart = 0; const chars1 = oldSentences .map((sentence) => { const line = sentence; if (line in lineHash) { return String.fromCharCode(lineHash[line]); } lineHash[line] = lineStart; lineArray[lineStart] = line; lineStart++; return String.fromCharCode(lineHash[line]); }) .join(''); const chars2 = newSentences .map((sentence) => { const line = sentence; if (line in lineHash) { return String.fromCharCode(lineHash[line]); } lineHash[line] = lineStart; lineArray[lineStart] = line; lineStart++; return String.fromCharCode(lineHash[line]); }) .join(''); return { chars1, chars2, lineArray }; }; export const computeChildEqualityFactor = (node1, node2) => { return 0; }; export const assertNodeTypeEqual = (node1, node2) => { if (getNodeProperty(node1, 'type') !== getNodeProperty(node2, 'type')) { throw new Error(`node type not equal: ${node1.type} !== ${node2.type}`); } }; export const ensureArray = (value) => { return Array.isArray(value) ? value : [value]; }; export const isNodeEqual = (node1, node2) => { const isNode1Array = Array.isArray(node1); const isNode2Array = Array.isArray(node2); if (isNode1Array !== isNode2Array) { return false; } if (isNode1Array) { return ( node1.length === node2.length && node1.every((node, index) => isNodeEqual(node, node2[index])) ); } const type1 = getNodeProperty(node1, 'type'); const type2 = getNodeProperty(node2, 'type'); if (type1 !== type2) { return false; } if (isTextNode(node1)) { const text1 = getNodeProperty(node1, 'text'); const text2 = getNodeProperty(node2, 'text'); if (text1 !== text2) { return false; } } const attrs1 = getNodeAttributes(node1); const attrs2 = getNodeAttributes(node2); const attrs = [...new Set([...Object.keys(attrs1), ...Object.keys(attrs2)])]; for (const attr of attrs) { if (attrs1[attr] !== attrs2[attr]) { return false; } } const marks1 = getNodeMarks(node1); const marks2 = getNodeMarks(node2); if (marks1.length !== marks2.length) { return false; } for (let i = 0; i < marks1.length; i++) { if (!isNodeEqual(marks1[i], marks2[i])) { return false; } } const children1 = getNodeChildren(node1); const children2 = getNodeChildren(node2); if (children1.length !== children2.length) { return false; } for (let i = 0; i < children1.length; i++) { if (!isNodeEqual(children1[i], children2[i])) { return false; } } return true; }; export const normalizeNodeContent = (node) => { const content = getNodeChildren(node) ?? []; const res = []; for (let i = 0; i < content.length; i++) { const child = content[i]; if (isTextNode(child)) { const textNodes = []; for ( let textNode = content[i]; i < content.length && isTextNode(textNode); textNode = content[++i] ) { textNodes.push(textNode); } i--; res.push(textNodes); } else { res.push(child); } } return res; }; export const getNodeProperty = (node, property) => { if (property === 'type') { return node.type?.name; } return node[property]; }; export const getNodeAttribute = (node, attribute) => node.attrs ? node.attrs[attribute] : undefined; export const getNodeAttributes = (node) => (node.attrs ? node.attrs : {}); export const getNodeMarks = (node) => node.marks ?? []; export const getNodeChildren = (node) => node.content?.content ?? []; export const getNodeText = (node) => node.text; export const isTextNode = (node) => node.type?.name === 'text'; export const matchNodeType = (node1, node2) => node1.type?.name === node2.type?.name || (Array.isArray(node1) && Array.isArray(node2)); export const createNewNode = (oldNode, children) => { if (!oldNode.type) { throw new Error('oldNode.type is undefined'); } return new Node( oldNode.type, oldNode.attrs, Fragment.fromArray(children), oldNode.marks, ); }; export const createDiffNode = (schema, node, type) => { return mapDocumentNode(node, (node) => { if (isTextNode(node)) { return createTextNode(schema, getNodeText(node), [ ...(node.marks || []), createDiffMark(schema, type), ]); } return node; }); }; function mapDocumentNode(node, mapper) { const copy = node.copy( Fragment.from( node.content.content .map((node) => mapDocumentNode(node, mapper)) .filter((n) => n), ), ); return mapper(copy) || copy; } export const createDiffMark = (schema, type) => { if (type === DiffType.Inserted) { return schema.mark('diffMark', { type }); } if (type === DiffType.Deleted) { return schema.mark('diffMark', { type }); } throw new Error('type is not valid'); }; export const createTextNode = (schema, content, marks = []) => { return schema.text(content, marks); }; export const diffEditor = (schema, oldDoc, newDoc) => { const oldNode = Node.fromJSON(schema, oldDoc); const newNode = Node.fromJSON(schema, newDoc); return patchDocumentNode(schema, oldNode, newNode); };

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