I want to push only unique objects into an array with $addToSet. My userSchema has a field bankDetails which should take an array of objects: I am updating the schema using the following controller function: The data is saving correctly but Mongo auto generates an _id field every time so technically none of t…
Tag: set
Pushing array into an array of array in TS
I am coming from Python, and am not entirely familiar with the ‘proper’ JS/TS way of doing things. I am looping through the elements of a set, and I am pushing lists of some of the elements onto a 2D array. I am getting the following error TypeError: Cannot read properties of undefined (reading &#…
How to get new Set from array of arrays by using Array.map function?
Exploring Sets now and could not get a new Set from an array of x arrays in it. I what to use Array.map method inside new Set(). Here is what I’m trying to do, and it seems logical, but in the end having values only from the 1st array: Will be awesome to understand what I am doing wrong and
JavaScript – Any subtle differences with Array.from(set) vs Array.from(set.values())
I know both methods result in the same exact thing and are valid ways to create an Array from a Set. But I’m curious if there’s any difference between and/or reason to use one method over the other when specifically utilizing the following methods: I’m guessing in this context, other than on…
Sorted (ordered) collection for JavaScript
I’m looking for sorted container for JavaScript. I’m using C++ std::set, https://en.cppreference.com/w/cpp/container/set and try porting my code to JavaScript. JavaScript Map is not ordered container. I need some ordered container. I don’t need completely compatible container of std::set on …
How to build a Set of unique Arrays?
I want to add many arrays to a Javascript set, and ensure that only unique arrays are added to the set. However, when I try adding the same array multiple times, it is always added instead of rejected. The .has() method always returns false as well. How do I fix this? Answer I’d use a Map instead, index…
Output Array of Simultaneously Possible Unique Element Combinations
My application references a database object that acts as a catalog. It’s a catalog of items that can be crafted if the user has the necessary components. Here is a small sample of the catalog: When the user has the necessary components for any given item, the user can assemble that item. The user is awa…
Array item gets the value “undefined”
I am trying to create an array of unique numbers from 0 to 10: But the output of the array will always have an undefined item at a random index which I don’t know why. Can somebody help me out? Answer If the new Set removes a duplicate, then i will be larger than the length of numbers, due to
Set of objects in javascript
I’d like to have a set of objects in Javascript. That is, a data structure that contains only unique objects. Normally using properties is recommended, e.g. myset[“key”] = true. However, I need the keys to be objects. I’ve read that Javascript casts property names to strings, so I gues…