Develop Reference

JavaScript - Issues recovering a map in an object after being saved in localStorage

I've been dealing with this for some time. I've a list of sections in which the user checks some checkboxes and that is sent to the server via AJAX. However, since the user can return to previous sections, I'm using some objects of mine to store some things the user has done (if he/she already finished working in that section, which checkboxes checked, etc). I'm doing this to not overload the database and only send new requests to store information if the user effectively changes a previous checkbox, not if he just starts clicking "Save" randomly. I'm using objects to see the sections of the page, and storing the previous state of the checkboxes in a Map. Here's my "supervisor":
function Supervisor(id) {
this.id = id;
this.verif = null;
this.selections = new Map();
var children = $("#ContentPlaceHolder1_checkboxes_div_" + id).children().length;
for (var i = 0; i < children; i++) {
if (i % 2 == 0) {
var checkbox = $("#ContentPlaceHolder1_checkboxes_div_" + id).children()[i];
var idCheck = checkbox.id.split("_")[2];
this.selections.set(idCheck, false);
}
}
console.log("Length " + this.selections.size);
this.change = false;
}
The console.log gives me the expected output, so I assume my Map is created and initialized correctly. Since the session of the user can expire before he finishes his work, or he can close his browser by accident, I'm storing this object using local storage, so I can change the page accordingly to what he has done should anything happen. Here are my functions:
function setObj(id, supervisor) {
localStorage.setItem(id, JSON.stringify(supervisor));
}
function getObj(key) {
var supervisor = JSON.parse(localStorage.getItem(key));
return supervisor;
}
So, I'm trying to add to the record whenever an user clicks in a checkbox. And this is where the problem happens. Here's the function:
function checkboxClicked(idCbx) {
var idSection = $("#ContentPlaceHolder1_hdnActualField").val();
var supervisor = getObj(idSection);
console.log(typeof (supervisor)); //Returns object, everythings fine
console.log(typeof (supervisor.change)); //Returns boolean
supervisor.change = true;
var idCheck = idCbx.split("_")[2]; //I just want a part of the name
console.log(typeof(supervisor.selections)); //Prints object
console.log("Length " + supervisor.selections.size); //Undefined!
supervisor.selections.set(idCheck, true); //Error! Note: The true is just for testing purposes
setObj(idSection, supervisor);
}
What am I doing wrong? Thanks!

Please look at this example, I removed the jquery id discovery for clarity. You'll need to adapt this to meet your needs but it should get you mostly there.
const mapToJSON = (map) => [...map];
const mapFromJSON = (json) => new Map(json);
function Supervisor(id) {
this.id = id;
this.verif = null;
this.selections = new Map();
this.change = false;
this.selections.set('blah', 'hello');
}
Supervisor.from = function (data) {
const id = data.id;
const supervisor = new Supervisor(id);
supervisor.verif = data.verif;
supervisor.selections = new Map(data.selections);
return supervisor;
};
Supervisor.prototype.toJSON = function() {
return {
id: this.id,
verif: this.verif,
selections: mapToJSON(this.selections)
}
}
const expected = new Supervisor(1);
console.log(expected);
const json = JSON.stringify(expected);
const actual = Supervisor.from(JSON.parse(json));
console.log(actual);
If you cant use the spread operation in 'mapToJSON' you could loop and push.
const mapToJSON = (map) => {
const result = [];
for (let entry of map.entries()) {
result.push(entry);
}
return result;
}
Really the only thing id change is have the constructor do less, just accept values, assign with minimal fiddling, and have a factory query the dom and populate the constructor with values. Maybe something like fromDOM() or something. This will make Supervisor more flexible and easier to test.
function Supervisor(options) {
this.id = options.id;
this.verif = null;
this.selections = options.selections || new Map();
this.change = false;
}
Supervisor.fromDOM = function(id) {
const selections = new Map();
const children = $("#ContentPlaceHolder1_checkboxes_div_" + id).children();
for (var i = 0; i < children.length; i++) {
if (i % 2 == 0) {
var checkbox = children[i];
var idCheck = checkbox.id.split("_")[2];
selections.set(idCheck, false);
}
}
return new Supervisor({ id: id, selections: selections });
};
console.log(Supervisor.fromDOM(2));
You can keep going and have another method that tries to parse a Supervisor from localStorageand default to the dom based factory if the localStorage one returns null.

pg-promise create custom filters for select query

The function that I am working on is getting an input object that has 7 different key-values and each of them could be undefined or not. I want to filter my database based on those key-values that exists in the input. For example if only input.userID exists I want to run this query:
db.query("...WHERE userID = ${userID}", {userID: input.userID});
else if both input.userID and input.startTime exist, I want to do this:
db.query("...WHERE userID = ${userID} and startTime= ${startTime}", {userID: input.userID, startTime: input.startTime});
What I have done is I created a params and keys object like this:
if(input.userID) {
keys.push('userID');
params.push(input.userID);
query = addFilterToTheQuery(query, 'userID', input.userID, filteredItemsCount);
filteredItemsCount = filteredItemsCount +1;
}
addFilterToTheQuery is a simple function I implemented myself. I basically make 7 if cases. Then I have to use those keys and param values to pass to the query function in a way that might need another huge switch case code.
Is this the only way to do this? Is there a better way to get rid of the redundancies in this code?

Custom Type Formatting is the most suitable here.
For example, if we want to convert an object with properties - filter values, we could do it like this:
var pgp = require('pg-promise')(/* initialization options */);
function FilterSet(filters) {
if (!filters || typeof filters !== 'object') {
throw new TypeError('Parameter \'filters\' must be an object.');
}
this._rawDBType = true; // property renamed later - see UPDATE below
this.formatDBType = function () {
var keys = Object.keys(filters);
var s = keys.map(function (k) {
return pgp.as.name(k) + ' = ${' + k + '}';
}).join(' AND ');
return pgp.as.format(s, filters);
};
}
TEST
var filter = new FilterSet({
first: 1,
second: 'two'
});
var test = pgp.as.format('WHERE $1', filter);
console.log(test);
This outputs:
WHERE "first" = 1 AND "second" = 'two'
If your filters are to be used as %value% with LIKE or ILIKE, then you would need to change your custom type accordingly.
See related questions:
42, 49, 89, 90,
UPDATE
Below is the same example re-written for the latest pg-promise (version 8.x or newer):
const pgp = require('pg-promise')(/* initialization options */);
class FilterSet {
constructor(filters) {
if (!filters || typeof filters !== 'object') {
throw new TypeError('Parameter \'filters\' must be an object.');
}
this.filters = filters;
this.rawType = true; // do not escape the result from toPostgres()
}
toPostgres(/*self*/) {
// self = this
const keys = Object.keys(this.filters);
const s = keys.map(k => pgp.as.name(k) + ' = ${' + k + '}').join(' AND ');
return pgp.as.format(s, this.filters);
}
}
See Custom Type Formatting.

Syntax problems. Knockout. For filtering

I'm working with jquery, Json data and knockout. What i did is to get a data, add to binded table and a filter field for name.
The thing is, that filter field works not as i want it to work. Because it matches the whole word. That is the code:
self.filter = ko.observable();
self.tickets = ko.computed(function () {
var filter = self.filter(),
arr = [];
if (filter) {
ko.utils.arrayForEach(self.ticketViewModel(), function (item) {
if (item.Name() == filter || item.Status() == filter) {
arr.push(item);
}
});
} else {
arr = self.ticketViewModel();
}
return arr;
});
So i'm trying to make that it would start filtering from the first letter. And i found several methods, which should work, but i can't get the result because i always get various errors of syntax. Maybe who have used these could help me out. The code for it:
self.filter = ko.observable().toString().toLowerCase();
self.tickets = ko.computed(function () {
var filter = self.filter(),
arr = [];
if (!filter) {
arr = self.ticketViewModel();
} else {
ko.utils.arrayFilter(self.ticketViewModel(), function (item) {
if (ko.utils.stringStartsWith(item.Name().toLowerCase()), filter)
arr.push(item);
})
}
return arr;
});
The last error i got was - Uncaught TypeError: string is not a function on line
var filter = self.filter()
The same error i got a few times, but after fixing that i get another ones when usually i get back to it again... And sorry for my english.
I can post the whole code if needed.

Managed to find an answer myself, finally.
Instead of using ko.util.stringStartsWith(), i'm using a simple Javascript checking. And it works perfectly. Maybe it will be useful for someone.
self.filterName = ko.observable('');
self.filterCompany = ko.observable('');
self.filterStatus = ko.observable('');
self.tickets = ko.computed(function () {
return ko.utils.arrayFilter(self.ticketViewModel(), function (rec) {
return (
(
(self.filterName().length == 0 || (rec.Name().toLowerCase().indexOf(self.filterName().toLowerCase()) > -1)) &&
(self.filterCompany().length == 0 || (rec.CompanyName().toLowerCase().indexOf(self.filterCompany().toLowerCase()) > -1)) &&
(self.filterStatus().length == 0 || (rec.Status().toLowerCase().indexOf(self.filterStatus().toLowerCase()) > -1))
)
)
});
});

Excel Type Filter popup for Jqgrid

I need to have a filter ( like in Excel spread Sheet) to embedded to the 'jquery' dialog popup. in this case i need to show all the unique values in the column and check box just before that value to select to the user. when user pressed filter button i need to filter only the values that user requested through the check boxes.
Can any one please let me any approach that i must follow.
Thanks in advance for your help and valuable time.

I was able to develop basic grid with excel kind of filter feature. any one who will come across this type of requirement can use this answer as a foundation.
I use this answer from 'Oleg' to embed the filter popup screen to the basic 'jqgrid'.
in the jqgrid page declare this array with the attributes (columns) that needs to display the filter screen popup.
var applyFilterColumnNames = ['Id','Type','custId','UserId'];
and the column model should be as follows -
colModel :[
{name:'Id', index:'Id',hidden: true,sortable: true},
{name:'custId', index:'custId', width:140,align:"left",sortable: true,search : false},
{name:'Type', index:'Type', width:120,align:"left",sortable: true,search : false},
{name:'UserId', index:'UserId', width:150,align:"left",sortable: true,search : false},
],
used that reference answer to embed the filter button function.
gr.closest("div.ui-jqgrid-view").find("div.ui-jqgrid-hdiv table.ui-jqgrid-htable tr.ui-jqgrid-labels > th.ui-th-column > div.ui-jqgrid-sortable")
.each(function () {
var idPrefix = "jqgh_" + gr[0].id + "_";
var idIndex = (this.id).substr(idPrefix.length,this.id.length) ;
if(includeInArray(applyFilterColumnNames,idIndex)){
jq('<button id=btn_'+idIndex+'>').css({float: "right", height: "17px"}).appendTo(this).button({
icons: {
primary: "ui-icon-gear"
},
text: false
}).click(function (e) {
var idPrefix = "jqgh_" + gr[0].id + "_";
// thId will be like "jqgh_list_name"
var thId = jq(e.target).closest('div.ui-jqgrid-sortable')[0].id ;
if (thId.substr(0, idPrefix.length) === idPrefix) {
var colName = thId.substr(idPrefix.length);
//alert('Clicked the button in the column "' + colName + '"');
constructFilter(colName);
return false;
}
});
//}
}
});
Below is the script i used to filter the jqgrid according to the filters
//Variables that use in filtering operation
var originalData = null;
var filteredData;
var selectedFilters = new Object();
var chkBoxElement;
var firstSortColumn;
function constructFilter(columnName){
// for the first initiation of the filter populate current grid data to an array
if(originalData == null || originalData == 'null'){
try{
// this array will hold the initail data set of the grid
originalData = gr.jqGrid('getGridParam','data');
// set the first sorting grid column
firstSortColumn = columnName;
// check if column is associated with a formatter. if so format the originalData values accordingly.
formatGridData(columnName);
}catch(e){}
}
var colData = new Array();
var filterDataSet;
// if current column is equal to initial sorted column set all posible values to the check boxes in the
// filter screen to select. ( since this is the master sorting column and other columns will filter according to that)
if(columnName == firstSortColumn){
filterDataSet = originalData;
}else{
// set current grid data set to show as checkboxes in the filter page
filterDataSet = gr.jqGrid('getCol',columnName,false);
}
for(key in filterDataSet){
// check box element object that will hold the checkbox label and its state ( true / false)
chkBoxElement = new Object();
chkBoxElement.id = getValueFromArray(filterDataSet[key],columnName);
if(typeof(chkBoxElement.id)== 'undefined'){
break;
}
// if this id is saved in previous filtering event checked option will set to true.
if(typeof(selectedFilters[columnName]) != 'undefined'){
if (includeInArray(selectedFilters[columnName],chkBoxElement.id)){
chkBoxElement.selected = true;
}else{
chkBoxElement.selected = false;
}
}
colData.push(chkBoxElement);
}
// removing duplicates
var uniqueValues = removeDuplicates(colData);
// sort the array without duplicate with the custom comparator
uniqueValues.sort(sortComparator);
// open the filter screen. return type will captured in the 'seletedElements' variable as pipe separated string
seletedElements = window.showModalDialog(filterUrl,uniqueValues,"dialogWidth:400px;dialogHeight:250px;center:yes;resizable:no;status:no;help:no;");
if(seletedElements != null && seletedElements != 'null'){
// get selected values to the array
selectedFilters[columnName] = seletedElements.split("|");
}else{
//user just close the popup (using close button) will return without doing anything
return;
}
if(columnName == firstSortColumn){
// refine filter with the non filtered data set
refillGrid(seletedElements,columnName,originalData);
}else{
// send current data set to refine
var currentDataSet = gr.jqGrid('getGridParam','data');
refillGrid(seletedElements,columnName,currentDataSet);
}
}
function formatGridData(columnName){
var isFormatter = gr.jqGrid("getColProp",columnName);
if(typeof isFormatter.formatter !== 'undefined') {
if(jq.isFunction( isFormatter.formatter ) ) {
for(key in originalData){
var plainValue = originalData[key][columnName];
var formattedVal = isFormatter.formatter.call(null,plainValue,null,null,null);
originalData[key][columnName] = formattedVal;
}
}
}
}
function resetFilters(){
for(key in applyFilterColumnNames){
jq("#btn_"+applyFilterColumnNames[key]).button("option", {
//icons: { primary: this.checked ? 'ui-icon-check' : 'ui-icon-closethick' }
icons: { primary: 'ui-icon-gear'}
});
}
gr.jqGrid("setCaption",gridCaption);
refreshGrid(originalData);
originalData = null;
firstSortColumn = null;
selectedFilters = new Object();
}
function refillGrid(seletedElements,columnName,filterDataSet){
var filteredData= new Array();
var elementsArray;
try{
elementsArray = seletedElements.split("|");
}catch(e){
// this exception happens when user simply open the filter screen
// do nothing and close it.
trace('Error in filter splitting -'+e);
return;
}
// When user de-select all check boxes from the popup screen
if(elementsArray == ""){
refreshGrid(originalData);
return;
}
// refine the grid data according to the filters
var mydata = filterDataSet;
for(i=0;i<elementsArray.length;i++){
var filterElement = elementsArray[i];
for(j = 0;j<mydata.length;j++){
if(filterElement==getValueFromArray(mydata[j],columnName)){
filteredData.push(mydata[j]);
}
}
}
// change the button icon to indicate that the column is filtered
changeButtonIcon(columnName);
// update the column header to indicate sort by column
changeGridCaption(columnName);
// fill the grid according to the passed array
refreshGrid(filteredData);
}
function changeGridCaption(columnName){
// get columns name array
var columnNames = gr.jqGrid('getGridParam','colNames');
// get column model array
var colModel = gr.jqGrid('getGridParam','colModel');
var colModelIndex=null;
if (firstSortColumn == columnName){
for(key in colModel){
try{
if (colModel[key].name == firstSortColumn){
colModelIndex = key;
break;
}
}catch(e){}
}
if(colModelIndex != null){
var columnName = columnNames[colModelIndex];
gr.jqGrid("setCaption",gridCaption + " - Filtered based on : "+columnName);
}
}
}
function changeButtonIcon(columnName){
//change the button Icon
jq("#btn_"+columnName).button("option", {
//icons: { primary: this.checked ? 'ui-icon-check' : 'ui-icon-closethick' }
icons: { primary: 'ui-icon-link'}
});
}
function getValueFromArray(obj,columnName){
if(obj !=null && typeof(obj)!='undefined'){
// if obj param is string just return it
if(typeof obj =='string'){
return obj;
}else{
return obj[columnName];
}
}
}
function sortComparator(a,b){
try{
var aId = a.id.toLowerCase();
var bId = b.id.toLowerCase();
if (aId < bId) {return 1}
if (aId > bId) {return -1}
}catch(e){
return 0;
}
}
function includeInArray(arr,obj) {
//alert(arr);
return (arr.indexOf(obj) != -1);
}
function refreshGrid(results) {
gr.jqGrid('clearGridData')
.jqGrid('setGridParam', { data: results })
.trigger('reloadGrid');
}
function removeDuplicates(valueArray){
var arr = {};
for ( i=0; i < valueArray.length; i++ ){
if(valueArray[i].id != null){
arr[valueArray[i].id] = valueArray[i];
}
}
valueArray = new Array();
for ( key in arr ){
valueArray.push(arr[key]);
}
return valueArray;
}
If something wrong here please let me know.this solution is working fine. but i really appreciate the comments in therms of performance and code best practices.

Dynamic arrays in Javascript/JQuery

Why does my array length always come out to 0 even though var email is equal to a string. (I've alerted out var email and the data is there).
var emails = new Array();
//get all the emails
$('.emailBox input').each(function (i)
{
var email = $(this).val();
if(email != '')
{
emails[email] = email;
alert(emails.length);
}
});

Because you're adding a property to the array.
var a = [];
a.foo = 42;
a.length === 0; // true
Instead try
emails.push(email);
This is the same as emails[emails.length] = email
As an aside:
var emails = new Array();
Is bad. You should be using [] instead of new Array() mainly because it's more terse and readable.
if (email != '') {
The above can be replace with if (email) { in case jQuery ever returns undefined or null
To make the entire code more elegant you should use
var emails = $('.emailBox input').map(function() {
return this.value;
}).filter(function (k, v) { return v; }).get();
Or without jQuery
var emails = [].map.call(document.querySelectorAll(".emailBox input"), function (v) {
return v.value;
}).filter(function (v) { return v; });
Although you'll need a QSA shim and a ES5 shim for legacy platform support.
Edit:
If you want the array to be unique then reduce it.
var arr = arr.reduce(function (memo, val, key, arr) {
// if the first index of the value is the index then add it.
// if the first index is different then we already have it.
if (arr.indexOf(val) === key) {
memo.push(val);
}
return memo;
}, []);

You could do all of that using a few jQuery methods.
var emails = $('.emailBox input')
.map(function() { return $(this).val() || null; })
.get();
jsFiddle.

emails[email] = email isn't doing what you want it to do. Try
emails.push(email);