loopback-datasource-juggler/lib/kvao/iterate-keys.js

39 lines
1.3 KiB
JavaScript

'use strict';
var assert = require('assert');
var utils = require('../utils');
/**
* Asynchronously iterate all keys in the database. Similar to `.keys()` but
* instead allows for iteration over large data sets without having to load
* everything into memory at once.
*
* @param {Object} filter An optional filter object with the following
* @param {String} filter.match Glob string to use to filter returned
* keys (i.e. `userid.*`). All connectors are required to support `*` and
* `?`. They may also support additional special characters that are
* specific to the backing database.
* @param {Object} options
* @returns {AsyncIterator} An Object implementing `next(cb) -> Promise`
* function that can be used to iterate all keys.
*
* @header KVAO.iterateKeys(filter)
*/
module.exports = function keyValueIterateKeys(filter, options) {
filter = filter || {};
options = options || {};
assert(typeof filter === 'object', 'filter must be an object');
assert(typeof options === 'object', 'options must be an object');
var iter = this.getConnector().iterateKeys(this.modelName, filter, options);
// promisify the returned iterator
return {
next: function(callback) {
callback = callback || utils.createPromiseCallback();
iter.next(callback);
return callback.promise;
},
};
};