@ckeditor/ckeditor5-engine
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The editing engine of CKEditor 5 – the best browser-based rich text editor.
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JavaScript
/**
* @license Copyright (c) 2003-2025, CKSource Holding sp. z o.o. All rights reserved.
* For licensing, see LICENSE.md or https://ckeditor.com/legal/ckeditor-licensing-options
*/
/**
* @module engine/model/operation/utils
*/
import { ModelNode } from '../node.js';
import { ModelRange } from '../range.js';
import { ModelText } from '../text.js';
import { ModelTextProxy } from '../textproxy.js';
import { CKEditorError, isIterable } from '@ckeditor/ckeditor5-utils';
/**
* Inserts given nodes at given position.
*
* @internal
* @param position Position at which nodes should be inserted.
* @param nodes Nodes to insert.
* @returns Range spanning over inserted elements.
*/
export function _insert(position, nodes) {
const normalizedNodes = _normalizeNodes(nodes);
// We have to count offset before inserting nodes because they can get merged and we would get wrong offsets.
const offset = normalizedNodes.reduce((sum, node) => sum + node.offsetSize, 0);
const parent = position.parent;
// Insertion might be in a text node, we should split it if that's the case.
_splitNodeAtPosition(position);
const index = position.index;
// Insert nodes at given index. After splitting we have a proper index and insertion is between nodes,
// using basic `Element` API.
parent._insertChild(index, normalizedNodes);
// Merge text nodes, if possible. Merging is needed only at points where inserted nodes "touch" "old" nodes.
_mergeNodesAtIndex(parent, index + normalizedNodes.length);
_mergeNodesAtIndex(parent, index);
return new ModelRange(position, position.getShiftedBy(offset));
}
/**
* Removed nodes in given range. Only {@link module:engine/model/range~ModelRange#isFlat flat} ranges are accepted.
*
* @internal
* @param range Range containing nodes to remove.
*/
export function _remove(range) {
if (!range.isFlat) {
/**
* Trying to remove a range which starts and ends in different element.
*
* @error operation-utils-remove-range-not-flat
*/
throw new CKEditorError('operation-utils-remove-range-not-flat', this);
}
const parent = range.start.parent;
// Range may be inside text nodes, we have to split them if that's the case.
_splitNodeAtPosition(range.start);
_splitNodeAtPosition(range.end);
// Remove the text nodes using basic `Element` API.
const removed = parent._removeChildren(range.start.index, range.end.index - range.start.index);
// Merge text nodes, if possible. After some nodes were removed, node before and after removed range will be
// touching at the position equal to the removed range beginning. We check merging possibility there.
_mergeNodesAtIndex(parent, range.start.index);
return removed;
}
/**
* Moves nodes in given range to given target position. Only {@link module:engine/model/range~ModelRange#isFlat flat} ranges are accepted.
*
* @internal
* @param sourceRange Range containing nodes to move.
* @param targetPosition Position to which nodes should be moved.
* @returns Range containing moved nodes.
*/
export function _move(sourceRange, targetPosition) {
if (!sourceRange.isFlat) {
/**
* Trying to move a range which starts and ends in different element.
*
* @error operation-utils-move-range-not-flat
*/
throw new CKEditorError('operation-utils-move-range-not-flat', this);
}
const nodes = _remove(sourceRange);
// We have to fix `targetPosition` because model changed after nodes from `sourceRange` got removed and
// that change might have an impact on `targetPosition`.
targetPosition = targetPosition._getTransformedByDeletion(sourceRange.start, sourceRange.end.offset - sourceRange.start.offset);
return _insert(targetPosition, nodes);
}
/**
* Sets given attribute on nodes in given range. The attributes are only set on top-level nodes of the range, not on its children.
*
* @internal
* @param range Range containing nodes that should have the attribute set. Must be a flat range.
* @param key Key of attribute to set.
* @param value Attribute value.
*/
export function _setAttribute(range, key, value) {
// Range might start or end in text nodes, so we have to split them.
_splitNodeAtPosition(range.start);
_splitNodeAtPosition(range.end);
// Iterate over all items in the range.
for (const item of range.getItems({ shallow: true })) {
// Iterator will return `ModelTextProxy` instances but we know that those text proxies will
// always represent full text nodes (this is guaranteed thanks to splitting we did before).
// So, we can operate on those text proxies' text nodes.
const node = item.is('$textProxy') ? item.textNode : item;
if (value !== null) {
node._setAttribute(key, value);
}
else {
node._removeAttribute(key);
}
// After attributes changing it may happen that some text nodes can be merged. Try to merge with previous node.
_mergeNodesAtIndex(node.parent, node.index);
}
// Try to merge last changed node with it's previous sibling (not covered by the loop above).
_mergeNodesAtIndex(range.end.parent, range.end.index);
}
/**
* Normalizes given object or an array of objects to an array of {@link module:engine/model/node~ModelNode nodes}. See
* {@link ~ModelNodeSet NodeSet} for details on how normalization is performed.
*
* @internal
* @param nodes Objects to normalize.
* @returns Normalized nodes.
*/
export function _normalizeNodes(nodes) {
const normalized = [];
function convert(nodes) {
if (typeof nodes == 'string') {
normalized.push(new ModelText(nodes));
}
else if (nodes instanceof ModelTextProxy) {
normalized.push(new ModelText(nodes.data, nodes.getAttributes()));
}
else if (nodes instanceof ModelNode) {
normalized.push(nodes);
}
else if (isIterable(nodes)) {
for (const node of nodes) {
convert(node);
}
}
else {
// Skip unrecognized type.
// eslint-disable-next-line @typescript-eslint/no-unused-vars
const unreachable = nodes;
}
}
convert(nodes);
// Merge text nodes.
for (let i = 1; i < normalized.length; i++) {
const node = normalized[i];
const prev = normalized[i - 1];
if (node instanceof ModelText && prev instanceof ModelText && _haveSameAttributes(node, prev)) {
// Doing this instead changing `prev.data` because `data` is readonly.
normalized.splice(i - 1, 2, new ModelText(prev.data + node.data, prev.getAttributes()));
i--;
}
}
return normalized;
}
/**
* Checks if nodes before and after given index in given element are {@link module:engine/model/text~ModelText text nodes} and
* merges them into one node if they have same attributes.
*
* Merging is done by removing two text nodes and inserting a new text node containing data from both merged text nodes.
*
* @param element Parent element of nodes to merge.
* @param index Index between nodes to merge.
*/
function _mergeNodesAtIndex(element, index) {
const nodeBefore = element.getChild(index - 1);
const nodeAfter = element.getChild(index);
// Check if both of those nodes are text objects with same attributes.
if (nodeBefore && nodeAfter && nodeBefore.is('$text') && nodeAfter.is('$text') && _haveSameAttributes(nodeBefore, nodeAfter)) {
// Append text of text node after index to the before one.
const mergedNode = new ModelText(nodeBefore.data + nodeAfter.data, nodeBefore.getAttributes());
// Remove separate text nodes.
element._removeChildren(index - 1, 2);
// Insert merged text node.
element._insertChild(index - 1, mergedNode);
}
}
/**
* Checks if given position is in a text node, and if so, splits the text node in two text nodes, each of them
* containing a part of original text node.
*
* @param position Position at which node should be split.
*/
function _splitNodeAtPosition(position) {
const textNode = position.textNode;
const element = position.parent;
if (textNode) {
const offsetDiff = position.offset - textNode.startOffset;
const index = textNode.index;
element._removeChildren(index, 1);
const firstPart = new ModelText(textNode.data.substr(0, offsetDiff), textNode.getAttributes());
const secondPart = new ModelText(textNode.data.substr(offsetDiff), textNode.getAttributes());
element._insertChild(index, [firstPart, secondPart]);
}
}
/**
* Checks whether two given nodes have same attributes.
*
* @param nodeA Node to check.
* @param nodeB Node to check.
* @returns `true` if nodes have same attributes, `false` otherwise.
*/
function _haveSameAttributes(nodeA, nodeB) {
const iteratorA = nodeA.getAttributes();
const iteratorB = nodeB.getAttributes();
for (const attr of iteratorA) {
if (attr[1] !== nodeB.getAttribute(attr[0])) {
return false;
}
iteratorB.next();
}
return iteratorB.next().done;
}