I have an Array of Objects called ENTITIES and the following function that receives and String id and the whole objects Array:
function getEntityById( id, ENTITIES) {
id = id.toString(); //made sure id is string
ENTITIES.forEach(function( ENT ) {
if( ENT.name == id ) {
return( ENT );
}
});
}
I've already checked the function with console.log and its working fine. (id is checked and the 'if' is getting TRUE). The problem occurs when i try to access the returned Object 'ENT' outside the function, like this:
var entity0 = getEntityById( 'test', ENTITIES);
console.log( entity0.id );
I get the following error: Uncaught TypeError: Cannot read property 'id' of undefined
It's like getEntityById function never really returned an Object.
Could you guys help me? Any clues?
You have this function:
function getEntityById( id, ENTITIES) {
id = id.toString(); //made sure id is string
ENTITIES.forEach(
and then you have this function
function( ENT ) {
if( ENT.name == id ) {
return( ENT );
}
which returns back to your original function:
});
}
which doesn't do anything with it, so getEntityById returns nothing... so you get undefined.
What you could do is:
function getEntityById( id, ENTITIES) {
id = id.toString(); //made sure id is string
var return_ENT;
ENTITIES.forEach(function( ENT ) {
if( ENT.name == id ) {
return_ENT = ENT;
}
});
return return_ENT;
}
A better option might be to use filter:
function getEntityById( id, ENTITIES) {
id = id.toString(); //made sure id is string
return ENTITIES.filter(function(ent) { return ent.name == id})[0];
};
If you want to return the found entity you have to save it, exit the forEach loop and return the variable:
function getEntityById(id, ENTITIES) {
var result = null;
id = id.toString(); //made sure id is string
ENTITIES.forEach(function( ENT ) {
if( ENT.name == id ) {
result = ENT;
}
});
return result;
}
But in that case you'll do some redundant work (if the required entity is found - there's no need to continue the loop). So I would recommend to do like:
function getEntityById(id, ENTITIES) {
var i = ENTITIES.length;
while(--i >= 0) {
if (ENTITIES[i].id === id) {
return ENTITIES[i];
}
}
}
Related
i have a problem with a mongoDb query, i need to search for a parameter value of any MongoDB field.
I use a function in $where clause like:
db.response.find(
{
$where: function() {
var deepIterate = function (obj, value) {
for (var field in obj) {
if (obj[field] == value){
return true;
}
var found = false;
if ( typeof obj[field] === ‘object’) {
found = deepIterate(obj[field], value)
if (found) { return true; }
}
}
return false;
};
return deepIterate(this, “Text36")
}
});
The returned response was fine but I don't know how I can pass the value (Text36 in this sample) I want to found like a parameter
can someone help me please ? Thanks
I have two arrays as such :
UserGroupUser[{Id:"1",UserId:"2",UserGroupId"1"},
{Id:"2",UserId:"3",UserGroupId"1"},
{Id:"3",UserId:"4",UserGroupId"2"}]
UserGroupId will have values such as 1, 2, 3 etc.
Employee[{EmployeeId:"1", EmpName:"John", Email:"john#example.com"},
{EmployeeId:"2", EmpName:"Mary", Email:"Mary#example.com"},
{EmployeeId:"3", EmpName:"Sarah", Email:"Sarah#example.com"},
{EmployeeId:"4", EmpName:"Jake", Email:"Jake#example.com"} ]
I will store a number in a variable GroupId such as GroupId=1
and what i want to do is check the UserGroupUser table if GroupId 1 matches any rows for key UserGroupId and if there is a match for every UserId the corresponding EmployeeId in Employee table that matches would mean i add a new element called enrolled=true. else if there is not match add a element to Employee enrolled=false.
for eg:
If GroupId is =1 then i want to get the userId of those with the UserGroupId as 1 in the UserGroupUser array and add enrolled:true into the Employee array EmployeeId to those corresponding to the UserId .
This is how i tried to do it..
UserGroupUser.forEach(function (arrayItem) {
if (arrayItem.UserGroupId === GroupId) {
result = Employee.map(function (a, index, array) {
while (arrayItem.UserId === a.EmployeeNo) {
a.enrolled = true;
}
return a;
}
);
}
else {
result = Employee.map(function (a, index, array) {
a.enrolled = false;
return a;
}
);
}
});
what am i doing wrong? how should i do this?
Try this
var userGroup = [{Id:"1",UserId:"2",UserGroupId:"1"},
{Id:"2",UserId:"3",UserGroupId:"1"},
{Id:"3",UserId:"4",UserGroupId:"2"}]
var employees = [{EmployeeId:"1", EmpName:"John", Email:"john#example.com"},
{EmployeeId:"2", EmpName:"Mary", Email:"Mary#example.com"},
{EmployeeId:"3", EmpName:"Sarah", Email:"Sarah#example.com"},
{EmployeeId:"4", EmpName:"Jake", Email:"Jake#example.com"} ]
employees.forEach(function(item){
var found = userGroup.filter(i=>i.UserId==item.Id);
if(found.length>0)
item.enrolled = true
else
item.enrolled = false
})
console.log(employees);
the employees then will contained the enrolled or not try this in your console too
The problem with your code is that when if (arrayItem.UserGroupId === GroupId) { is executed, it changes enrolled to true for the concerned employees but when the else part of this check is executed, it overrides the changes made by the if condition part.
Try this.
UserGroupUser = [{Id:"1",UserId:"2",UserGroupId:"1"},
{Id:"2",UserId:"3",UserGroupId:"1"},
{Id:"3",UserId:"4",UserGroupId:"2"}];
Employee = [{EmployeeId:"1", EmpName:"John", Email:"john#example.com"},
{EmployeeId:"2", EmpName:"Mary", Email:"Mary#example.com"},
{EmployeeId:"3", EmpName:"Sarah", Email:"Sarah#example.com"},
{EmployeeId:"4", EmpName:"Jake", Email:"Jake#example.com"}];
GroupId = "1";
Employee.map(function (emp) {
emp.enrolled = false;
});
UserGroupUser.forEach(function (arrayItem) {
if (arrayItem.UserGroupId === GroupId) {
Employee.map(function (emp) {
if (arrayItem.UserId === emp.EmployeeId) {
emp.enrolled = true;
}
});
}
});
console.log(Employee);
I am trying to change the property name /attr name of my json object.I try like that but nothing will change.I need to make json object after seen the input json and convert it like outjson
function changeData(data){
var title;
for(var i = 0; i < data.length; i++){
if(data[i].hasOwnProperty("displayName")){
data[i]["label"] = data[i]["displayName"];
delete data[i]["displayName"];
}
if(data[i].hasOwnProperty("displayDetail")){
data[i]["title"] = data[i]["displayDetail"];
delete data[i]["displayDetail"];
}
if(data[i].hasOwnProperty("inputType")){
if(data[i]["inputType"]=="NUMBER"){
data[i]["type"]="number"
}else if(data[i]["inputType"]=="TEXT"){
data[i]["type"]="text"
}else if(data[i]["inputType"]=="SWTICH"){
data[i]["type"]="select"
}
delete data[i]["inputType"];
}
}
console.log(data);
}
Try this - it's possibe to remove the if selection for inputType by creating a tiny lookup table from original value to new value:
function changeData(data) {
var map = { NUMBER: "number", TEXT: "text", SWITCH: "select" };
// data is an object - use for .. in to enumerate
for (var key in data.input) {
var e = data.input[key]; // alias for efficient structure dereferencing
e.label = e.displayName;
e.title = e.displayDetail;
e.type = map[e.inputType];
delete e.displayName;
delete e.displayDetail;
delete e.inputType;
}
};
There's really no need for the hasOwnProperty test these days - only use it if you think there's any risk that someone unsafely added to Object.prototype. jQuery manages without it quite happily, other modern code should do to.
If the mapping of field names was any longer I'd consider using another mapping table with another loop to remove the hard coded copy/delete pairs.
i have a nice Recursive function for that:
usage:
// replace list
var replacedObj = replaceAttrName(sourceObject, {foo: 'foooo', bar: 'baaar'});
so in your case you can easily do:
var newObj = replaceAttrName(json, {displayDetail: 'title', displayName: 'label', inputType: 'type'});
demo: http://jsfiddle.net/h1u0kq67/15/
the function is that:
function replaceAttrName(sourceObj, replaceList, destObj) {
destObj = destObj || {};
for(var prop in sourceObj) {
if(sourceObj.hasOwnProperty(prop)) {
if(typeof sourceObj[prop] === 'object') {
if(replaceList[prop]) {
var strName = replaceList[prop];
destObj[strName] = {};
replaceAttrName(sourceObj[prop], replaceList, destObj[strName]);
} else if(!replaceList[prop]) {
destObj[prop] = {};
replaceAttrName(sourceObj[prop], replaceList, destObj[prop]);
}
} else if (typeof sourceObj[prop] != 'object') {
if(replaceList[prop]) {
var strName = replaceList[prop];
destObj[strName] = sourceObj[prop];
} else if(!replaceList[prop]) {
destObj[prop] = sourceObj[prop];
}
}
}
}
return destObj;
}
If I am getting you right, you just want substitutions:
displayDetail => title
displayName => label
inputType => type.
I came up with the follwoing:
function changeData(data){
return JSON.parse(JSON.stringify(data).replace(/displayDetail/g, "title").replace(/displayName/g, "label").replace(/inputType/g, "type"));
}
Here is the Fiddle to play with.
Edit: I forgot replacements for "NUMBER", "TEXT" and "SWITCH".
function changeData(data){
return JSON.parse(JSON.stringify(data).replace(/displayDetail/g, "title").replace(/displayName/g, "label").replace(/inputType/g, "type").replace(/TEXT/g, "text").replace(/NUMBER/g, "number").replace(/SWITCH/g, "switch"));
}
Often in a response from a remote API call, I receive nested objects:
var response = {
data : {
users : [
{
name : 'Mr. White'
}
]
}
}
I want to check whether the first user's name is 'Mr. White', and would naturally want to write something like.
var existed = response.data.users[0].name === 'Mr. White'
However I cannot be sure if all the objects are present, so to avoid exceptions instead I end up writing:
var existed = response && response.data && response.data.users && response.data.users[0].name === 'Mr. White'
Is there a nicer way to do this? Another ugly option that comes to mind is:
var existed = false;
try {
var existed = response.data.users[0].name === 'Mr. White';
} catch(e) { }
In addition to vanilla javascript, I usually have underscore.js and jquery available too.
Edit:
Oops, noticed I asked a dupe of javascript test for existence of nested object key.
An interesting option based on those answers is:
var existed = (((response || {}).data || {}).users || [{}])[0].name === 'Mr. White';
You could hide this naughty try/catch block inside a function like this one :
function resolve(root, path){
try {
return (new Function(
'root', 'return root.' + path + ';'
))(root);
} catch (e) {}
}
var tree = { level1: [{ key: 'value' }] };
resolve(tree, 'level1[0].key'); // "value"
resolve(tree, 'level1[1].key'); // undefined
More on this : https://stackoverflow.com/a/18381564/1636522
I would use the try catch approach but wrap it in a function to hide the ugliness.
Instead of a try/catch, this should be done via checking whether each level in the object is defined or not.
go for
if(typeof(response)!="undefined"
&& typeof(response.data)!="undefined"
&& typeof(response.data.users)!="undefined"
&& typeof(response.data.users[0])!="undefined"
&& typeof(response.data.users[0].name)!="undefined"
) {
//executes only if response.data.users[0].name is existing
}
Here is a function which I used in one of my projects http://jsfiddle.net/JBBAJ/
var object = {
data: {
users: [
{
firstName: "White"
},
{
firstName: "Black"
}
]
}
}
var read = function(path, obj) {
var path = path.split(".");
var item = path.shift();
if(item.indexOf("]") == item.length-1) {
// array
item = item.split("[");
var arrayName = item.shift();
var arrayIndex = parseInt(item.shift().replace("]", ""));
var arr = obj[arrayName || ""];
if(arr && arr[arrayIndex]) {
return read(path.join("."), arr[arrayIndex]);
} else {
return null;
}
} else {
// object
if(obj[item]) {
if(path.length === 0) {
return obj[item];
} else {
return read(path.join("."), obj[item]);
}
} else {
return null;
}
}
}
console.log(read("data.users[0].firstName", object)); // White
console.log(read("data.users[1].firstName", object)); // Black
console.log(read("data.test.users[0]", object)); // null
The idea is to pass your path as a string along with your object. The idea was to prevent the throwing of an exception and receive just null as result of the path is wrong. The good thing is that the function works with every path and you don't need to write long if statements.
i have an array which contains some values. i want if the textbox's value contains a value from any of the element of that array it will show alert "exists", otherwise "doesn't exists"
I have tried the following code:
$('[id$=txt_Email]').live('blur', function (e) {
var email = $('[id$=txt_Email]').val();
var array = ['gmail.com', 'yahoo.com'];
if (array.indexOf(email) < 0) { // doesn't exist
// do something
alert('doesnot exists');
}
else { // does exist
// do something else
alert('exists');
}
});
But this is comparing the whole value with the array's element. i want to use contains function as we can in C# with string.Please help me.
I want if user type "test#gmail.com" it will show exists in array. if user enter "test#test.com" it will alert doesnot exists.
I think you want
$.each(array, function () {
found = this.indexOf(email);
});
To find the match not exact string you need to do some thing like
Live Demo
arr = ['gmail.com', 'yahoo.com'];
alert(FindMatch(arr, 'gmail.co'));
function FindMatch(array, strToFind)
{
for(i=0; i < array.length; i++)
{
if(array[i].indexOf( strToFind) != -1)
return true;
}
return false;
}
$(document).on('blur', '[id$=txt_Email]', function (e) {
var email = this.value, array = ['gmail.com', 'yahoo.com'];
if (email.indexOf('#')!=-1) {
if ($.inArray(email.split('#')[1], array)!=-1) {
alert('exists');
}else{
alert('does not exists');
}
}
});
FIDDLE
b is the value, a is the array
It returns true or false
function(a,b){return!!~a.indexOf(b)}