Merging Documents in PouchDB

Question

Merging Documents in PouchDB

I need to retrieve equipment data from pouchdb/couchbase that has users assigned to them. Each piece of equipment has an _id and a checkedOutBy field with the user._id as its value. The employee object contains the user's name. How can I retrieve the equipment objects along with the user names and display them together?

I have tried looking into map/reduce functions that use emit, but I'm struggling to understand the concept. Here is the code snippet I wrote based on what I learned, using AngularJS:

field = "eq::"
this.getAllEquip = function(field){
            function map(doc) {
                if (doc.checkedOutBy !== undefined) {
                    emit(doc.checkedOutBy, {empName : doc.name});
                }
            }
            var result = database.query(map, {include_docs: true,
                            attachments: true,
                            startkey: field,
                            endkey: field + '\uffff'})
                .catch(function (err) {
                //error handling here
            });
            return result
        };

I am unable to see how the two documents are being connected. What am I missing? Why is my result empty?

The equipment JSON structure looks like this:

{checkedOutBy: "us::10015", description: "3P Microsoft Surface w/stylus & power cord", equipId: "SUR1501", purchaseDate: "", rCost: 1000, id:"eq::10001"}

Employee JSON example:

{"firstname":"Joe","gender":"male","lastname":"Blow","status":"active","title":"office","type":"userInfo","_id":"us::10015","_rev":"2-95e9f34784094104ad24bbf2894ae786"}

Thank you for any assistance.

javascript angularjs json mapreduce pouchdb

Answer 1

Answer №1

If I have grasped the question correctly, a solution similar to this might be sufficient:

// Example Array of Objects containing Equipment
var equipmentArray = [{checkedOut: "abc1", description: "item1", id: 1},
{checkedOut: "abc2", description: "item2", id: 2},
{checkedOut: "abc3", description: "item3", id: 3},
{checkedOut: "abc1", description: "item1", id: 4},
{checkedOut: "abc4", description: "item3", id: 5},
{checkedOut: "abc6", description: "item3", id: 6}];

// Array of objects representing Employees - the "id" in equipmentArray matches with "checkedOut" in employeesArray  
var employeesArray = [{name: "john", id: "abc1"},
{name: "jack", id: "abc2"},
{name: "alice", id: "abc3"},
{name: "james", id: "abc4"}];

var finalResult = [];  // array for final results

// iterate through equipmentArray
equipmentArray.forEach(function(item) {

var tempObject = item;

var checkedOutId = item.checkedOut;

// using array.find to locate the first element that fulfills the specified function, assuming each employee has a unique ID and there are no duplicates
var foundEmployee = employeesArray.find(function(employee) {

if (employee.id == checkedOutId)

return employee.name

})

// Formulate the object to be included in the final array by adding a new key called "name" based on the outcome of the find operation above 
if (foundEmployee != undefined) {

tempObject.name = foundEmployee.name

}
else {

tempObject.name = "Not found";

}

finalResult.push(tempObject);

})

Answer 2

If I have grasped the question correctly, a solution similar to this might be sufficient:

// Example Array of Objects containing Equipment
var equipmentArray = [{checkedOut: "abc1", description: "item1", id: 1},
{checkedOut: "abc2", description: "item2", id: 2},
{checkedOut: "abc3", description: "item3", id: 3},
{checkedOut: "abc1", description: "item1", id: 4},
{checkedOut: "abc4", description: "item3", id: 5},
{checkedOut: "abc6", description: "item3", id: 6}];

// Array of objects representing Employees - the "id" in equipmentArray matches with "checkedOut" in employeesArray  
var employeesArray = [{name: "john", id: "abc1"},
{name: "jack", id: "abc2"},
{name: "alice", id: "abc3"},
{name: "james", id: "abc4"}];

var finalResult = [];  // array for final results

// iterate through equipmentArray
equipmentArray.forEach(function(item) {

var tempObject = item;

var checkedOutId = item.checkedOut;

// using array.find to locate the first element that fulfills the specified function, assuming each employee has a unique ID and there are no duplicates
var foundEmployee = employeesArray.find(function(employee) {

if (employee.id == checkedOutId)

return employee.name

})

// Formulate the object to be included in the final array by adding a new key called "name" based on the outcome of the find operation above 
if (foundEmployee != undefined) {

tempObject.name = foundEmployee.name

}
else {

tempObject.name = "Not found";

}

finalResult.push(tempObject);

})

Answer 3

Answer №2

I want to express my gratitude to Vijay for guiding me towards the PouchDB solution I needed. First step is gathering all the equipment items. Then, following Vijay's technique, looping through the array to add names to objects and create a new array proved to be effective. It was vital to access specific parts of the object such as obj.doc.checkedOutBy and tempObj.doc.name to successfully complete the task.

$pouchDB.getAllDocs('eq::').then(function(udata){
    var result = [];
    // iterating through equipment array 
    udata.rows.forEach(function(obj) {
        var tempObj = obj;
        var checkedout_id=obj.doc.checkedOutBy;

        if (checkedout_id != undefined) {
            $pouchDB.get(checkedout_id).then(function(emp){
                return emp.firstname + " " + emp.lastname
            }).then(function(name){
                tempObj.doc.name = name;
            });
        }
        result.push(tempObj);
    })

Within my service:

this.get = function(documentId) {
    return database.get(documentId);
};

and:

this.getAllDocs = function(field){
    return database.allDocs({
      include_docs: true,
      attachments: true,
      startkey: field,
      endkey: field + '\uffff'});
};

Answer 4

I want to express my gratitude to Vijay for guiding me towards the PouchDB solution I needed. First step is gathering all the equipment items. Then, following Vijay's technique, looping through the array to add names to objects and create a new array proved to be effective. It was vital to access specific parts of the object such as obj.doc.checkedOutBy and tempObj.doc.name to successfully complete the task.

$pouchDB.getAllDocs('eq::').then(function(udata){
    var result = [];
    // iterating through equipment array 
    udata.rows.forEach(function(obj) {
        var tempObj = obj;
        var checkedout_id=obj.doc.checkedOutBy;

        if (checkedout_id != undefined) {
            $pouchDB.get(checkedout_id).then(function(emp){
                return emp.firstname + " " + emp.lastname
            }).then(function(name){
                tempObj.doc.name = name;
            });
        }
        result.push(tempObj);
    })

Within my service:

this.get = function(documentId) {
    return database.get(documentId);
};

and:

this.getAllDocs = function(field){
    return database.allDocs({
      include_docs: true,
      attachments: true,
      startkey: field,
      endkey: field + '\uffff'});
};

Merging Documents in PouchDB

Answer №1

Answer №2

Similar questions

What is the best way to extract an integer value from a JSON object?

Extrude a face in Three.js along its respective normal vector

Preventing the tab key from triggering ng-keypress

Node.js: Understanding the issue of a mysterious null value in JSON responses sent to clients

The browser is not showing JavaScript alerts and prompts when they are called inside a function

What is the best way to combine duplicate JSON objects together?

What is the best way to incorporate a button in my code that automatically triggers changes at regular intervals?

Managing a directive in Angular using a service: A guide

Ensuring no null objects are present in the jQuery each function

Attempting to utilize the JavascriptExecutor for button testing, however encountering an error message stating 'Unexpected keyword or identifier'

Looking for a list of events in Express.js?

Adjusting the X-axis in Highstock: Tips and Tricks

AngularJS is not responding to a 400 bad request

React Modals: Only the modal component triggered by the first click will open, with no other modals opening

Problem encountered with JavaScript getter on iOS 5

Step-by-step guide on incorporating edit, update, and discard functionalities within an Angular Material table component (mat-table)

What is the best way to retrieve the value of a selected radio button with YUI?

I have found that I can load a CSS file using Node Express, however, it seems to be malfunctioning. On the other hand, some

Promise not being properly returned by io.emit

Troubleshoot: Trouble with selecting the clicked item in AngularJS when using ng-repeat