We Keep Coding

Why is the value of a specific key for a doc getting 'undefined' [duplicate]

Is there something that I'm missing that would allow item to log as an object with a parameter, but when I try to access that parameter, it's undefined?
What I've tried so far:
console.log(item) => { title: "foo", content: "bar" } , that's fine
console.log(typeof item) => object
console.log(item.title) => "undefined"
I'll include some of the context just in case it's relevant to the problem.
var TextController = function(myCollection) {
this.myCollection = myCollection
}
TextController.prototype.list = function(req, res, next) {
this.myCollection.find({}).exec(function(err, doc) {
var set = new Set([])
doc.forEach(function(item) {
console.log(item) // Here item shows the parameter
console.log(item.title) // "undefined"
set.add(item.title)
})
res.json(set.get());
})
}
Based on suggestion I dropped debugger before this line to check what item actually is via the node repl debugger. This is what I found : http://hastebin.com/qatireweni.sm
From this I tried console.log(item._doc.title) and it works just fine.. So, this seems more like a mongoose question now than anything.
There are questions similar to this, but they seem to be related to 'this' accessing of objects or they're trying to get the object outside the scope of the function. In this case, I don't think I'm doing either of those, but inform me if I'm wrong. Thanks

Solution
You can call the toObject method in order to access the fields. For example:
var itemObject = item.toObject();
console.log(itemObject.title); // "foo"
Why
As you point out that the real fields are stored in the _doc field of the document.
But why console.log(item) => { title: "foo", content: "bar" }?
From the source code of mongoose(document.js), we can find that the toString method of Document call the toObject method. So console.log will show fields 'correctly'. The source code is shown below:
var inspect = require('util').inspect;
...
/**
* Helper for console.log
*
* #api public
*/
Document.prototype.inspect = function(options) {
var isPOJO = options &&
utils.getFunctionName(options.constructor) === 'Object';
var opts;
if (isPOJO) {
opts = options;
} else if (this.schema.options.toObject) {
opts = clone(this.schema.options.toObject);
} else {
opts = {};
}
opts.minimize = false;
opts.retainKeyOrder = true;
return this.toObject(opts);
};
/**
* Helper for console.log
*
* #api public
* #method toString
*/
Document.prototype.toString = function() {
return inspect(this.inspect());
};

Make sure that you have defined title in your schema:
var MyCollectionSchema = new mongoose.Schema({
_id: String,
title: String
});

Try performing a for in loop over item and see if you can access values.
for (var k in item) {
console.log(item[k]);
}
If it works, it would mean your keys have some non-printable characters or something like this.
From what you said in the comments, it looks like somehow item is an instance of a String primitive wrapper.
E.g.
var s = new String('test');
typeof s; //object
s instanceof String; //true
To verify this theory, try this:
eval('(' + item + ')').title;
It could also be that item is an object that has a toString method that displays what you see.
EDIT: To identify these issues quickly, you can use console.dir instead of console.log, since it display an interactive list of the object properties. You can also but a breakpoint and add a watch.

Use findOne() instead of find().
The find() method returns an array of values, even if you have only one possible result, you'll need to use item[0] to get it.
The findOne method returns one object or none, then you'll be able to access its properties with no issues.

Old question, but since I had a problem with this too, I'll answer it.
This probably happened because you're using find() instead of findOne(). So in the end, you're calling a method for an array of documents instead of a document, resulting in finding an array and not a single document. Using findOne() will let you get access the object normally.

A better way to tackle an issue like this is using doc.toObject() like this
doc.toObject({ getters: true })
other options include:
getters: apply all getters (path and virtual getters)
virtuals: apply virtual getters (can override getters option)
minimize: remove empty objects (defaults to true)
transform: a transform function to apply to the resulting document before returning
depopulate: depopulate any populated paths, replacing them with their original refs (defaults to false)
versionKey: whether to include the version key (defaults to true)
so for example you can say
Model.findOne().exec((err, doc) => {
if (!err) {
doc.toObject({ getters: true })
console.log('doc _id:', doc._id) // or title
}
})
and now it will work

You don't have whitespace or funny characters in ' title', do you? They can be defined if you've quoted identifiers into the object/map definition. For example:
var problem = {
' title': 'Foo',
'content': 'Bar'
};
That might cause console.log(item) to display similar to what you're expecting, but cause your undefined problem when you access the title property without it's preceding space.

I think using 'find' method returns an array of Documents.I tried this and I was able to print the title
for (var i = 0; i < doc.length; i++) {
console.log("iteration " + i);
console.log('ID:' + docs[i]._id);
console.log(docs[i].title);
}

If you only want to get the info without all mongoose benefits, save i.e., you can use .lean() in your query. It will get your info quicker and you'll can use it as an object directly.
https://mongoosejs.com/docs/api.html#query_Query-lean
As says in docs, this is the best to read-only scenarios.

Are you initializing your object?
function MyObject()
{
this.Title = "";
this.Content = "";
}
var myo1 = new MyObject();
If you do not initialize or have not set a title. You will get undefined.

When you make tue query, use .lean() E.g
const order = await Order.findId("84578437").lean()

find returns an array of object , so to access element use indexing, like
doc[0].title

Inherited truth check in condition comparison

I'm looking for a clean way to get true or false based on an order of permissions based on the following rules:
Starts with Company Permissions as a default
Then to Team Permissions if permission defined
Finally to User Permissions if permission is
This would need to also handle undefined. So basically wanting to see if there's some "clean" way to do this without having to conditionally check each value and moving on.
In this example, the result should be false since there are no User Permissions defined and the Team Permissions has false.
const UserPermissions = {}
const TeamPermissions = {
PERMISSION_ONE: false
}
const CompanyPermissions = {
PERMISSION_ONE: true
}
const hasPermissions = UserPermissions.PERMISSION_ONE || TeamPermissions.PERMISSION_ONE || CompanyPermissions.PERMISSION_ONE
console.log(hasPermissions)
Thanks!

From my understanding, the rules are:
ignore undefined
return true of false, whatever comes first
This little function should handle that, not sure how you want to deal with empty (or all undefined) arguments.
let x;
let t = true;
let f = false;
let firstBool = (...a) => Boolean(a.filter(x => typeof x !== 'undefined').shift());
console.log(firstBool(x,t,f));
console.log(firstBool(t,x,f));
console.log(firstBool(x,f,t));
console.log(firstBool());
In your example, that would be
const hasPermissions = firstBool(
UserPermissions.PERMISSION_ONE,
TeamPermissions.PERMISSION_ONE,
CompanyPermissions.PERMISSION_ONE
]

If you are looking for the same property name in multiple objects, you might be able to slightly alter the technique in georg's answer:
const firstBoolProp = (...objs) => (prop) =>
objs.reduce((a, o) => Boolean(a) === a ? a : o[prop], undefined)
const UserPermissions = {}
const TeamPermissions = {PERMISSION_ONE: false}
const CompanyPermissions = {PERMISSION_ONE: true}
console .log (
firstBoolProp
(UserPermissions, TeamPermissions, CompanyPermissions)
('PERMISSION_ONE')
)
You can then use a single function to multiple permissions against that same set of permission objects:
const getPermissions = firstBoolProp(UserPermissions, TeamPermissions, CompanyPermissions)
const perms = {
p1: getPermissions('PERMISSION_ONE'),
p2: getPermissions('PERMISSION_TWO'),
}
//=> {p1: false, p2: undefined}
And if you want to use an array rather than individual parameters, you can simply replace (...obj) => with (obj) =>

One way to do this is to store the permissions in an array and reduce it to a boolean:
/**
*
* #param {{PERMISSION_ONE:boolean}[]} permissions
*/
function anyoneHasPermission(permissions, name = "PERMISSION_ONE") {
for (const perm of permissions) {
if (perm[name]) {
return true;
}
}
}
console.log(anyoneHasPermission([UserPermissions, TeamPermissions, CompanyPermissions]))
You need to be more specific in what you want to accomplish. Choosing the right data structure is usually more important than choosing an algorithm. Indeed, sometimes the right data structure makes the algorithm disappear completely.

Throw the permissions into an array in the order that you want them validated.
Iterate the array and if any of your conditions is not met then return false and break.
This will stop you running down the entire chain if say your top level permission is not set (because nothing beyond that matters anymore and no use validating it)
const UserPermissions = {PERMISSION_ONE: true}
const TeamPermissions = {}
const CompanyPermissions = {PERMISSION_ONE: true}
const permCheck = HasPerms([CompanyPermissions, TeamPermissions, UserPermissions]);
alert(permCheck);
function HasPerms(permArray){
for (var i = 0; i < permArray.length; i++) {
if (!permArray[i] || !permArray[i].PERMISSION_ONE) {return false;}
}
return true;
}
You can expand the function to dynamically take in the permission you would like to check but example shown hardcoded for simplicity sake.

How to perform case insensitive lookup in javascript set?

How to perform case-insensitve lookup in javascript's set?
I have a situation where I have a set of allowed strings which doesn't ensure what case they would be in. I need to validate a user input against that set. How can I achieve this?
const countries = new Set();
countries.add("USA");
countries.add("japan");
// returns false, but is there any way I could get
//`my set to ignore case and return true?`
console.log(countries.has("usa"));
console.log(countries.has("USA"));

Just always call .toLowerCase on the string before you add it or before performing a .has check. For sure you can also abstract that into a class (if thats really necessary):
class CaseInsensitiveSet extends Set {
constructor(values) {
super(Array.from(values, it => it.toLowerCase()));
}
add(str) {
return super.add(str.toLowerCase());
}
has(str) {
return super.has(str.toLowerCase());
}
delete(str) {
return super.delete(str.toLowerCase());
}
}
const countries = new CaseInsensitiveSet([
"Usa",
]);
console.log(countries.has("usa")); // true

The short answer is "no". has uses SameValueZero algorithm to seek for a value's existence. See the comparison table here.
If performance is not a concern, you can try two searches, one with uppercased value, and one with lowercased value, and decide whether the value actually exists.
And the better approach would be to always insert the values by converting them to uppercase/lowercase and match accordingly for existence.

Sets check the exact data you have provided. The simplest solution is to save the data in lowercase or UPPERCASE and then search over the set using the .toLoserCase() String method.
Example:
// Save data in lowecase
const set1 = new Set(['test', 'other']);
console.log(set1.has('Test'));
// expected output: false
console.log(set1.has('Other'.toLowerCase()));
// expected output: false

You can add a hasIgnoreCase() prototype on Set.
Set.prototype.hasIgnoreCase = function(str) {
return this.has(str) || this.has(str.toUpperCase());
}
const countries = new Set();
countries.add("USA");
countries.add("japan");
// returns false, but is there any way I could get
//`my set to ignore case and return true?`
console.log(countries.hasIgnoreCase("usa"));
console.log(countries.hasIgnoreCase("USA"));

Using Filter Function to Find Values Equal to False and Setting to True

In my Angular app I have a function that drills down to an array, and then uses a filter function to pull out values in a new array where "completed" is "false".
This is working as expected. And the way our data is, there is always one object in the array that has the property for "completed" set to "false", so I can target [0] to get to that. So, from there all I need to do is set it to "true". However, for whatever reason, how to accomplish this last step is eluding me.
This is my whole function, and what I've tried thus far:
private completeLastWorkflowStatus() {
let currentService = this.checkDiscipline();
for (let service of this.client.services) {
if (service.service === currentService) {
let targetWorkflow = service.workflow;
let inCompleteWorkflow = targetWorkflow.filter(workflow => workflow.completed === false);
console.log(inCompleteWorkflow);
if (inCompleteWorkflow[0].completed === false) {
inCompleteWorkflow[0].completed === true;
console.log(inCompleteWorkflow[0].completed);
}
}
}
}
For the last console.log listed above, I still get "false" as the value. What am I missing here? How can I set the value of "completed" to "true" for this one object in the array?

inCompleteWorkflow[0].completed === true; is not assignment. Do inCompleteWorkflow[0].completed = true;

Set the null value to a object

I'm working on a external API, where the default value of a object is null.
location.recipt = null;
But I need to set location.recipt.printRecipt to true, I created a fiddle and figured out unless I make location.recipt = {} I wont be able to set printRecipt, is there any other solution for this?
Because if that is the case I need to make 2 calls to the API, once to change from null to empty object {} and then again to update the data.
Fiddle : https://jsfiddle.net/bdeepakreddy/nwemtwtu/

location.recipt={
printRecipt : true
};

I suggest to use a check first
location.receipt = location.receipt || {};
location.receipt.printRecipt = true;

No. null is null (nothing), and you can't set properties on nothing. Instead, you could make your default value be an object with a value property:
location.receipt = { value: null };

You can do it in JavaScript in one statement:
var location2 = { recipt: { printRecipt: true } };
console.log(location2);