mirror of
https://github.com/Tencent/tmagic-editor.git
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77 lines
2.2 KiB
TypeScript
77 lines
2.2 KiB
TypeScript
/*
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* Tencent is pleased to support the open source community by making TMagicEditor available.
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*
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* Copyright (C) 2021 THL A29 Limited, a Tencent company. All rights reserved.
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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import { cloneDeep } from 'lodash-es';
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export class UndoRedo<T = any> {
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private elementList: T[];
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private listCursor: number;
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private listMaxSize: number;
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constructor(listMaxSize = 200) {
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const minListMaxSize = 2;
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this.elementList = [];
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this.listCursor = 0;
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this.listMaxSize = listMaxSize > minListMaxSize ? listMaxSize : minListMaxSize;
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}
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public pushElement(element: T): void {
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// 新元素进来时，把游标之外的元素全部丢弃，并把新元素放进来
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this.elementList.splice(this.listCursor, this.elementList.length - this.listCursor, cloneDeep(element));
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this.listCursor += 1;
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// 如果list中的元素超过maxSize，则移除第一个元素
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if (this.elementList.length > this.listMaxSize) {
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this.elementList.shift();
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this.listCursor -= 1;
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}
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}
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public canUndo(): boolean {
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return this.listCursor > 1;
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}
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// 返回undo后的当前元素
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public undo(): T | null {
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if (!this.canUndo()) {
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return null;
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}
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this.listCursor -= 1;
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return this.getCurrentElement();
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}
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public canRedo() {
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return this.elementList.length > this.listCursor;
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}
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// 返回redo后的当前元素
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public redo(): T | null {
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if (!this.canRedo()) {
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return null;
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}
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this.listCursor += 1;
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return this.getCurrentElement();
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}
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public getCurrentElement(): T | null {
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if (this.listCursor < 1) {
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return null;
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}
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return cloneDeep(this.elementList[this.listCursor - 1]);
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}
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}
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