87 lines
2.7 KiB
JavaScript
87 lines
2.7 KiB
JavaScript
//@flow
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/*
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Copyright 2017 Aviral Dasgupta
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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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http://www.apache.org/licenses/LICENSE-2.0
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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 {Value} from 'slate';
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import _clamp from 'lodash/clamp';
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type MessageFormat = 'rich' | 'markdown';
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class HistoryItem {
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// We store history items in their native format to ensure history is accurate
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// and then convert them if our RTE has subsequently changed format.
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value: Value;
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format: MessageFormat = 'rich';
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constructor(value: ?Value, format: ?MessageFormat) {
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this.value = value;
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this.format = format;
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}
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static fromJSON(obj: Object): HistoryItem {
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return new HistoryItem(
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Value.fromJSON(obj.value),
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obj.format,
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);
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}
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toJSON(): Object {
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return {
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value: this.value.toJSON(),
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format: this.format,
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};
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}
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}
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export default class SlateComposerHistoryManager {
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history: Array<HistoryItem> = [];
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prefix: string;
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lastIndex: number = 0; // used for indexing the storage
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currentIndex: number = 0; // used for indexing the loaded validated history Array
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constructor(roomId: string, prefix: string = 'mx_composer_history_') {
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this.prefix = prefix + roomId;
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// TODO: Performance issues?
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let item;
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for (; item = sessionStorage.getItem(`${this.prefix}[${this.currentIndex}]`); this.currentIndex++) {
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try {
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this.history.push(
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HistoryItem.fromJSON(JSON.parse(item)),
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);
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} catch (e) {
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console.warn("Throwing away unserialisable history", e);
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}
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}
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this.lastIndex = this.currentIndex;
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// reset currentIndex to account for any unserialisable history
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this.currentIndex = this.history.length;
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}
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save(value: Value, format: MessageFormat) {
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const item = new HistoryItem(value, format);
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this.history.push(item);
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this.currentIndex = this.history.length;
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sessionStorage.setItem(`${this.prefix}[${this.lastIndex++}]`, JSON.stringify(item.toJSON()));
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}
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getItem(offset: number): ?HistoryItem {
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this.currentIndex = _clamp(this.currentIndex + offset, 0, this.history.length - 1);
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return this.history[this.currentIndex];
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}
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}
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