rxdeep/dist/es6/util/watcher.js

RxJS deep state management

export class Watcher {
    constructor(initial, keyFunc) {
        this.keyFunc = keyFunc;
        this._keymap = {};
        this.changes(initial);
    }
    changes(list = []) {
        const changes = {
            additions: [],
            deletions: [],
            moves: [],
        };
        const keymap = list.reduce((map, item, index) => {
            const _key = this.keyFunc(item);
            map[_key] = { index, item };
            if (!(_key in this._keymap))
                changes.additions.push({ index, item });
            return map;
        }, {});
        Object.entries(this._keymap).forEach(([_key, entry]) => {
            if (!(_key in keymap))
                changes.deletions.push(entry);
            else {
                const _newEntry = keymap[_key];
                if (_newEntry.index !== entry.index) {
                    changes.moves.push({
                        oldIndex: entry.index,
                        newIndex: _newEntry.index,
                        item: entry.item
                    });
                }
            }
        });
        this._keymap = keymap;
        return changes;
    }
    get keymap() { return this._keymap; }
}
//# sourceMappingURL=watcher.js.map