How to use the @theia/filesystem/lib/common/filesystem-watcher-protocol.FileChangeType.DELETED function in @theia/filesystem

protected async onDidTaskFileChange(fileChanges: FileChange[]): Promise {
        for (const change of fileChanges) {
            if (change.type === FileChangeType.DELETED) {
                this.removeTasks(change.uri);
            } else {
                // re-parse the config file
                await this.refreshTasks(change.uri);
            }
        }
    }

const key = rootStat.uri;
            toDelete.delete(key);
            if (!this.models.has(key)) {
                const model = new TaskConfigurationModel(key, this.preferences);
                model.onDidChange(() => this.onDidChangeTaskConfigEmitter.fire({ uri: key, type: FileChangeType.UPDATED }));
                model.onDispose(() => this.models.delete(key));
                this.models.set(key, model);
                this.onDidChangeTaskConfigEmitter.fire({ uri: key, type: FileChangeType.UPDATED });
            }
        }
        for (const uri of toDelete) {
            const model = this.models.get(uri);
            if (model) {
                model.dispose();
            }
            this.onDidChangeTaskConfigEmitter.fire({ uri, type: FileChangeType.DELETED });
        }
    }, 500);