Develop Reference

Javascript How to check the length of multiple variables and return the result in an efficient way?

At the moment I have an if the condition that checks if any of the string variable lengths is greater than 2 if true check for another condition, else console.log the output.
var previous_data_change = 'last_changed on 10/01/2019 13:56:34';
var current_data_change= "";
var current_data_end = "";
var current_data_profile = "normal";
// check for changes
if (
previous_data_change.length >= 2 ||
current_data_start.length >= 2 ||
current_data_end.length >= 2 ||
current_data_profile.length >= 2
) {
if (previous_data_change.includes("last_changed")) {
console.log(`last change comments: ${previous_data_change}`)
}
} else {
console.log(`no change in previous record`)
}
i have tried refactoring it using some,
var previous_data_change = 'last_changed on 10/01/2019 13:56:34';
var current_data_change= "";
var current_data_end = "";
var current_data_profile = "normal";
var filter_col = [
previous_data_change,
current_data_change,
current_data_end,
current_data_profile
];
change_boolean = filter_col.some((element) => element.length >= 2);
if (change_boolean && previous_data_change.includes("last_changed")) {
console.log(`last change comments: ${previous_data_change}`);
} else {
console.log("no change in previous record");
}
is there any way to shorten it further?

Since you want any of them to be length greater than 2. You can simply merge them instead of writing 4 if conditions.
var previous_data_change = 'last_changed on 10/01/2019 13:56:34';
var current_data_change= "";
var current_data_end = "";
var current_data_profile = "normal";
var string_to_check = previous_data_change + current_data_start + current_data_end + current_data_profile;
// check for changes
if (string_to_check.length < 2) {
console.log(`no change in previous record`)
return false;
}
if (previous_data_change.includes("last_changed")) {
console.log(`last change comments: ${previous_data_change}`)
return true;
}

How to optimise RadComboBox clearItems function

I have a MultiSelectDropDown, that is, several RadComboBox controls are used in a combined way. For example, I can have a dropdown for regions, another for depots and another for user. The idea is to change the content of lower levels dynamically whenever items are selected or unselected on a higher level. The problem is that in the case when many items are selected, this becomes brutally slow due to some Telerik functions, but I do not understand why. This is a chunk from the client-side of the MultiSelectDropDown prototype:
changeLowerLevels: function (valueIndex, values, value) {
if (!this.canChange) return;
//Get selected values from combobox
var combo = $find(this.ddlIDs[valueIndex - 1]);
var cbItems = combo.get_checkedItems();
var selectedItems = [];
var change = null;
var counter = 0;
if (cbItems.length) this.filterString = "";
for (var i = 0; i < cbItems.length; i++) {
counter++;
if (this.filterString == "") this.filterString = cbItems[i].get_text();
selectedItems.push(cbItems[i].get_value());
}
if (counter > 1) this.filterString += " with " + (counter - 1) + " other" + ((counter > 2) ? "s" : "");
if (JSON.stringify(selectedItems) === JSON.stringify(this.selectedItems[valueIndex - 1]) || selectedItems == [])
return;
this.selectedItems[valueIndex - 1] = selectedItems;
var controlObject = this;
var combo = $find(this.ddlIDs[valueIndex]);
var comboItems = combo.get_items();
if(!this.disabled) combo.enable();
combo.clearItems();
if (valueIndex == 1) this.twoLevelCache = values;
var val = values;
//break if all items are found
var nrOfSelectedItems = this.selectedItems[valueIndex - 1].length;
var nrOfFoundItems = 0;
var index = 0;
var indexes = [];
var found = false;
while (nrOfFoundItems < nrOfSelectedItems && val[index] !== undefined) {
found = (this.selectedItems[valueIndex - 1].indexOf(val[index].Value) != -1);
if (!(found))
index++;
else {
indexes.push(index)
nrOfFoundItems++;
index++;
}
}
//separators from valuesIndex - 1 level
var controlObject = this;
for (var i = 0; i < indexes.length; i++) {
var separator = new Telerik.Web.UI.RadComboBoxItem();
separator.set_text("<span><a class=\"checkAll tt-multi-uncheck-icon\" index=\"" + index + "\">U</a>" + $find(this.ddlIDs[valueIndex - 1]).findItemByValue(val[indexes[i]].Value).get_text() + "</span>");
separator.set_value("");
separator.set_isSeparator(true);
comboItems.add(separator);
this.twoLevelCache.push(val[indexes[i]].Levels);
//valuesIndex level
var valuesArray = val;
var comboItem = new Telerik.Web.UI.RadComboBoxItem();
for (var depot in valuesArray[indexes[i]].Levels) {
comboItem = new Telerik.Web.UI.RadComboBoxItem();
comboItem.set_text(valuesArray[indexes[i]].Levels[depot].Name);
comboItem.set_value(valuesArray[indexes[i]].Levels[depot].Value);
comboItems.add(comboItem);
comboItem = null;
}
$('#' + this.ddlIDs[valueIndex] + '_DropDown a.checkAll').unbind().on("click", function () {
checkAllLowerItems(this, controlObject.ddlIDs[valueIndex]);
});
}
combo.set_emptyMessage(this.allText);
//$("#" + this.ddlIDs[valueIndex]).html(returnValue);
if (this.ddlIDs.length > valueIndex + 1) {
var paramToPass = (((val == undefined) || (val[index] === undefined)) ? ("") : (val[index]));
if (this.allText.length > 0)
this.changeLowerLevels(valueIndex + 1, paramToPass, "");
else {
if (paramToPass !== "")
paramToPass = paramToPass.Levels;
if ((val[index] == undefined) || (val[index].Levels[0] === undefined) || (val[index].Levels[0].Value === "")) {
this.changeLowerLevels(valueIndex + 1, paramToPass, "");
}
else {
this.changeLowerLevels(valueIndex + 1, paramToPass, val[index].Levels[0].Value);
}
}
}
else {
if (this.allText.length > 0)
this.selectedItems[valueIndex] = "";
else
if ((val[index] == undefined) || (val[index].Levels[0] === undefined) || (val[index].Levels[0].Value === "")) {
this.selectedItems[valueIndex] = "";
}
else {
this.selectedItems[valueIndex] = val[index].Levels[0].Value;
}
}
this.setText();
}
combo.clearItems() is extremeley slow. I have take a look on how it is implemented:
function (){var f=this._parent._getControl();?if(f._checkBoxes){f._checkedIndicesJson="[]";?f._checkedIndices=[];?var g=f.get_items();?for(var d=0,e=g.get_count();?d<e;?d++){var c=f.get_items().getItem(d);?c.set_checked(false);?}f.updateClientState();?}a.RadComboBoxItemCollection.callBaseMethod(this,"clear");?}
How can I make sure that this Javascript function speeds up?

I have finally solved the problem by rewriting Telerik client-side functionalities. It was a long and difficult debugging, but it yielded a large performance boost in the most difficult circumstances. From ~30 000 milliseconds, to ~300. Let's see the parts of the optimization:
The actual rewrite
/* Overriding Telerik functions Start */
var overridenTelerikControls = false;
function overrideTelerikFunctionalities() {
if (!overridenTelerikControls) {
overridenTelerikControls = true;
Telerik.Web.UI.RadComboBox.prototype.clearItems = function (isMultiSelectDropDown) {
this.get_items().clear(isMultiSelectDropDown);
this._itemData = null;
};
Telerik.Web.UI.RadComboBoxItemCollection.prototype.clear = function (isMultiSelectDropDown){
var f=this._parent._getControl();
if(f._checkBoxes){
f._checkedIndicesJson="[]";
f._checkedIndices=[];
var g = f.get_items();
for(var d=0,e=g.get_count();d<e;d++){
var c=f.get_items().getItem(d);
c.set_checked(false, isMultiSelectDropDown);
}
if (isMultiSelectDropDown) {
f._updateComboBoxText();
if (f._checkAllCheckBoxElement != null) {
f._updateCheckAllState();
}
}
f.updateClientState();
}
Telerik.Web.UI.RadComboBoxItemCollection.callBaseMethod(this, "clear");
};
Telerik.Web.UI.RadComboBoxItem.prototype.set_checked = function (d, isMultiSelectDropDown){
if(!this.get_enabled()){
return;
}
this._setChecked(d);
var c=this.get_comboBox();
if(c){
if(d){
c._registerCheckedIndex(this.get_index());
}else{
c._unregisterCheckedIndex(this.get_index());
}
if (!isMultiSelectDropDown) {
c._updateComboBoxText();
}
if((!isMultiSelectDropDown) && (c._checkAllCheckBoxElement!=null)){
c._updateCheckAllState();
}
}
};
}
}
/* Overriding Telerik functions End*/
My approach was to keep the old way of their working by default, but if an isMultiSelectDropDown parameter is passed, then work in the optimized manners. So we have a switch materialized as a parameter and we can turn it on/off. The main difference was that the old way was to change the label text showing the selected elements each time a checkbox is checked/unchecked. The main improvement was to do this change after all the checkboxes were checked/unchecked. This extremely simple idea was the driving force behind the boost of performance.
Actual usage
overrideTelerikFunctionalities();
combo.clearItems(true);
This was the functionalities were overriden if they were not already and the parameter was true, therefore the new approach was chosen.
Test, test, test

Is there a javascript library that does spreadsheet calculations without the UI

I am working on a project that needs an excel like calculation engine in the browser. But, it doesn't need the grid UI.
Currently, I am able to do it by hiding the 'div' element of Handsontable. But, it isn't elegant. It is also a bit slow.
Is there a client side spreadsheet calculation library in javascript that does something like this?
x = [ [1, 2, "=A1+B1"],
[2, "=SUM(A1,A2"),3] ];
y = CalculateJS(x);
##############
y: [[1, 2, 3],
[2,3,3]]

I'm not aware of any (although I haven't really looked), but if you wish to implement your own, you could do something along these lines (heavily unoptimized, no error checking):
functions = {
SUM: function(args) {
var result = 0;
for (var i = 0; i < args.length; i++) {
result += parseInt(args[i]);
}
return result;
}
};
function get_cell(position) {
// This function returns the value of a cell at `position`
}
function parse_cell(position) {
cell = get_cell(position);
if (cell.length < 1 || cell[0] !== '=')
return cell;
return parse_token(cell.slice(1));
}
function parse_token(tok) {
tok = tok.trim();
if (tok.indexOf("(") < 0)
return parse_cell(tok);
var name = tok.slice(0, tok.indexOf("("));
if (!(name in functions)) {
return 0; // something better than this?
}
var arguments_tok = tok.slice(tok.indexOf("(") + 1);
var arguments = [];
while (true) {
var arg_end = arguments_tok.indexOf(",");
if (arg_end < 0) {
arg_end = arguments_tok.lastIndexOf(")");
if (arg_end < 0)
break;
}
if (arguments_tok.indexOf("(") >= 0 && (arguments_tok.indexOf("(") < arg_end)) {
var paren_amt = 1;
arg_end = arguments_tok.indexOf("(") + 1;
var end_tok = arguments_tok.slice(arguments_tok.indexOf("(") + 1);
while (true) {
if (paren_amt < 1) {
var last_index = end_tok.indexOf(",");
if (last_index < 0)
last_index = end_tok.indexOf(")");
arg_end += last_index;
end_tok = end_tok.slice(last_index);
break;
}
if (end_tok.indexOf("(") > 0 && (end_tok.indexOf("(") < end_tok.indexOf(")"))) {
paren_amt++;
arg_end += end_tok.indexOf("(") + 1;
end_tok = end_tok.slice(end_tok.indexOf("(") + 1);
} else {
arg_end += end_tok.indexOf(")") + 1;
end_tok = end_tok.slice(end_tok.indexOf(")") + 1);
paren_amt--;
}
}
}
arguments.push(parse_token(arguments_tok.slice(0, arg_end)));
arguments_tok = arguments_tok.slice(arg_end + 1);
}
return functions[name](arguments);
}
Hopefully this will give you a starting point!
To test in your browser, set get_cell to function get_cell(x) {return x;}, and then run parse_cell("=SUM(5,SUM(1,7,SUM(8,111)),7,8)"). It should result in 147 :)

I managed to do this using bacon.js. It accounts for cell interdependencies. As of now, it calculates values for javascript formula instead of excel formula by using an eval function. To make it work for excel formulae, all one has to do is replace eval with Handsontable's ruleJS library. I couldn't find a URI for that library... hence eval.
https://jsfiddle.net/sandeep_muthangi/3src81n3/56/
var mx = [[1, 2, "A1+A2"],
[2, "A2", "A3"]];
var output_reference_bus = {};
var re = /\$?[A-N]{1,2}\$?[1-9]{1,4}/ig
var alphabet = "ABCDEFGHIJKLMNOPQRSTUVWXYZ".split('');
function convertToCellRef(rows, cols) {
var alphabet_index = rows+1,
abet = "";
while (alphabet_index>0) {
abet = alphabet[alphabet_index%alphabet.length-1]+abet;
alphabet_index = Math.floor(alphabet_index/alphabet.length);
}
return abet+(cols+1).toString();
}
function getAllReferences(value) {
if (typeof value != "string")
return null;
var references = value.match(re)
if (references.length == 0)
return null;
return references;
}
function replaceReferences(equation, args) {
var index = 0;
return equation.replace(re, function(match, x, string) {
return args[index++];
});
}
//Assign an output bus to each cell
mx.forEach(function(row, row_index) {
row.forEach(function(cell, cell_index) {
output_reference_bus[convertToCellRef(row_index, cell_index)] = Bacon.Bus();
})
})
//assign input buses based on cell references... and calculate the result when there is a value on all input buses
mx.forEach(function(row, row_index) {
row.forEach(function(cell, cell_index) {
if ((all_refs = getAllReferences(cell)) != null) {
var result = Bacon.combineAsArray(output_reference_bus[all_refs[0]]);
for (i=1; i<all_refs.length; i++) {
result = Bacon.combineAsArray(result, output_reference_bus[all_refs[i]]);
}
result = result.map(function(data) {
return eval(replaceReferences(cell, data));
})
result.onValue(function(data) {
console.log(convertToCellRef(row_index, cell_index), data);
output_reference_bus[convertToCellRef(row_index, cell_index)].push(data);
});
}
else {
if (typeof cell != "string")
output_reference_bus[convertToCellRef(row_index, cell_index)].push(cell);
else
output_reference_bus[convertToCellRef(row_index, cell_index)].push(eval(cell));
}
})
})
output_reference_bus["A2"].push(20);
output_reference_bus["A1"].push(1);
output_reference_bus["A1"].push(50);

Filter by numerical range, custom filter - AngularJS

I am trying to create a filter for AngularJS data. I have 2 inputs, minAgeInput and maxAgeInput.
I would like to return all products/objects (with ng-repeat), where the product's minAge and maxAge are within the boundaries set by the input values.
My filter function looks like this:
or link to Plunker
$scope.ageRange = function (plane) {
var minAgeProduct = parseFloat(product.minAge);
var maxAgeProduct = parseFloat(product.maxAge);
var minAgeInput = parseFloat($scope.minAge);
var maxAgeInput = parseFloat($scope.maxAge);
if(minAgeInput >= minAgeProduct) {
if(maxAgeInput <= maxAgeProduct) {
return true;
} else {
return false;
}
return true;
} else {
return false;
}
};

Here is the functional solution to the question:
$scope.ageRange = function (plane) {
var minAgeProduct = parseFloat(plane.minAge);
var maxAgeProduct = parseFloat(plane.maxAge);
var minAgeInput = parseFloat($scope.minAge);
var maxAgeInput = parseFloat($scope.maxAge);
if (!isNaN(minAgeInput) && maxAgeProduct < minAgeInput)
return false;
if (!isNaN(maxAgeInput) && minAgeProduct > maxAgeInput)
return false;
return true;
};
A working solution can be found here Plunker

How does Javascript evaluate the right parenthesis?

I'm working on a calculator that takes an expression such as (5+4) and evaluates it by passing the buttons pressed to an array, and then building a parse tree from the data in the array.
What's interesting/strange, is that my code won't push the value of the right parenthesis to the array. Here is my code, could someone help me out?
The console.log activeButton shows that is the value of the button being pressed, but even when I placed calcArray.push() outside the if statements it would not push ) to an array.
$(document).ready(function(){
var calcArray = new Array();
$("input").click(function(){
var activeButton = this.value;
console.log(activeButton);
if(!isNaN(activeButton))
{
calcArray.push(parseInt(activeButton));
console.log(calcArray);
}
else if(activeButton === "=")
{
evaluate(buildTree(calcArray));
calcArray = [];
}
else
{
calcArray.push(activeButton);
}
});
});
The BuildTree code:
function BinaryTree(root) {
this.root = root;
this.activeNode = root;
}
function Node(element){
this.element = element;
this.parent;
this.rightChild;
this.leftChild;
this.setLeft = function(node){
this.leftChild = node;
node.parent = this;
};
this.setRight = function(node){
this.rightChild = node;
node.parent = this;
};
}
//methods
var buildTree = function(array)
{
var tree = new BinaryTree(new Node(null));
for(var i = 0; i < array.length; i++)
{
var newNode = new Node(array[i]);
if(array[i] == "(")
{
newNode.element = null;
tree.activeNode.setLeft(newNode);
tree.activeNode = newNode;
}
else if(array[i] == "+" || array[i] == "-" || array[i] == "/" || array[i] == "*")
{
tree.activeNode.element = newNode.element;
tree.activeNode.setRight(new Node(null));
tree.activeNode = tree.activeNode.rightChild;
}
else if(array[i] == ")")
{
if(tree.activeNode.parent == null)
{
;
}
else
{
tree.activeNode = tree.activeNode.parent;
tree.root = tree.activeNode;
}
}
else
{
tree.activeNode.element = newNode.element;
tree.activeNode = tree.activeNode.parent;
}
}
return tree.activeNode;
}
var evaluate = function(node){
var newNode1, newNode2;
newNode1 = new Node(null);
newNode1.parent = node;
newNode2 = new Node(null);
newNode2.parent = node;
if(node.leftChild == null && node.rightChild == null)
return node.element;
else{
newNode1.element = evaluate(node.leftChild);
newNode2.element = evaluate(node.rightChild);
if(newNode1.parent.element == "+")
{
return Number(newNode1.element) + Number(newNode2.element);
}
if(newNode1.parent.element == "-")
{
return newNode1.element - newNode2.element;
}
if(newNode1.parent.element == "*")
{
return newNode1.element * newNode2.element;
}
else
{
return newNode1.element / newNode2.element;
}
}
};

I just tried this out using your code and it worked fine passing the value as a string:
function pushButton (value) {
var activeButton = value;
console.log(activeButton);
if(!isNaN(activeButton))
{
calcArray.push(parseInt(activeButton));
console.log(calcArray);
}
else if(activeButton === "=")
{
evaluate(buildTree(calcArray));
calcArray = [];
}
else
{
calcArray.push(activeButton);
}
};
You aren't ever printing out the array in the last case (which is where the right paren would go), so are you sure it's not on the array and you just aren't seeing the visual feedback?
If so, we need to see more of your code. Try and setup a jsfiddle.