include_utils.js
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// Copyright IBM Corp. 2015,2016. All Rights Reserved.
// Node module: loopback-datasource-juggler
// This file is licensed under the MIT License.
// License text available at https://opensource.org/licenses/MIT
'use strict';
module.exports.buildOneToOneIdentityMapWithOrigKeys = buildOneToOneIdentityMapWithOrigKeys;
module.exports.buildOneToManyIdentityMapWithOrigKeys = buildOneToManyIdentityMapWithOrigKeys;
module.exports.join = join;
module.exports.KVMap = KVMap;
/**
* Effectively builds associative map on id -> object relation and stores original keys.
* Map returned in form of object with ids in keys and object as values.
* @param objs array of objects to build from
* @param idName name of property to be used as id. Such property considered to be unique across array.
* In case of collisions last wins. For non-unique ids use buildOneToManyIdentityMap()
* @returns {} object where keys are ids and values are objects itself
*/
function buildOneToOneIdentityMapWithOrigKeys(objs, idName) {
var kvMap = new KVMap();
for (var i = 0; i < objs.length; i++) {
var obj = objs[i];
var id = obj[idName];
kvMap.set(id, obj);
}
return kvMap;
}
function buildOneToManyIdentityMapWithOrigKeys(objs, idName) {
var kvMap = new KVMap();
for (var i = 0; i < objs.length; i++) {
var obj = objs[i];
var id = obj[idName];
var value = kvMap.get(id) || [];
value.push(obj);
kvMap.set(id, value);
}
return kvMap;
}
/**
* Yeah, it joins. You need three things id -> obj1 map, id -> [obj2] map and merge function.
* This functions will take each obj1, locate all data to join in map2 and call merge function.
* @param oneToOneIdMap
* @param oneToManyIdMap
* @param mergeF function(obj, objectsToMergeIn)
*/
function join(oneToOneIdMap, oneToManyIdMap, mergeF) {
var ids = oneToOneIdMap.getKeys();
for (var i = 0; i < ids.length; i++) {
var id = ids[i];
var obj = oneToOneIdMap.get(id);
var objectsToMergeIn = oneToManyIdMap.get(id) || [];
mergeF(obj, objectsToMergeIn);
}
}
/**
* Map with arbitrary keys and values. User .set() and .get() to work with values instead of []
* @returns {{set: Function, get: Function, remove: Function, exist: Function, getKeys: Function}}
* @constructor
*/
function KVMap() {
var _originalKeyFieldName = 'originalKey';
var _valueKeyFieldName = 'value';
var _dict = {};
var keyToString = function(key) { return key.toString(); };
var mapImpl = {
set: function(key, value) {
var recordObj = {};
recordObj[_originalKeyFieldName] = key;
recordObj[_valueKeyFieldName] = value;
_dict[keyToString(key)] = recordObj;
return true;
},
get: function(key) {
var storeObj = _dict[keyToString(key)];
if (storeObj) {
return storeObj[_valueKeyFieldName];
} else {
return undefined;
}
},
remove: function(key) {
delete _dict[keyToString(key)];
return true;
},
exist: function(key) {
var result = _dict.hasOwnProperty(keyToString(key));
return result;
},
getKeys: function() {
var result = [];
for (var key in _dict) {
result.push(_dict[key][_originalKeyFieldName]);
}
return result;
},
};
return mapImpl;
}