I have a JSON file with 20k entries in it. The even number indexes are all ID numbers. The element right after each ID number is the matching string for that ID that I need to put in to a table. ID Matching Str ID Matching Str 1 String for 1 3 String for 3 2 String for 2 4
Tag: higher-order-functions
How can I extract from an array of arrays all the arrays that have the same value in their first field?
The following function elegantly finds duplicates in 1-dimensional arrays: When I send it (for example) this array [‘123456’, ‘787877’, ‘763223’, ‘787877’, ‘854544’] it returns [‘787877’]. What I need is something similar that works for a…
How to map through an array of values of a single prop in an array of objects in React?
I was earlier using map() to loop through values of a single prop within an object. Now the object is expanded to an array of objects, how will I loop through my values still? Am I supposed to use a map inside of a map, if yes then how should I implement it? Answer There are many approaches, one being:
Understanding Behaviour of Find method in Javascript
In the above example, I’m updating the result returned by the find method but it also changes the value of the original array why so? Answer It’s because Objects in JavaScript are passed by reference, you got that object ( {age : 3} ) in exists then added 1 to it’s “age” key , so…
Higher-order function with recursion in Javascript
newbie here… I’m trying to grasp the concept of functional programming in Javascript, but I got stuck. I’m trying to apply a function to another function with recursion (higher-order function). Let’s say I have an input that can be a variable or an array, for example: My basic function…
How to create initial value for .reduce based on enum?
I have a reduced function that needs initial values based on an enum. See simplified code below: The enum looks like this: I don’t want to explicitely list every member of the enum though. I tried with the following: Is there a way to simply add empty arrays for all of the enum’s members? Best cas…
Why can I use comma at the end of the line in the following callback function inside the map function?
In javascript, I thought we aren’t allowed to end the line with comma if we were inside a closure. Why is the following code snippet an exception? And why does it not work if I put a comma after k.c = ‘asd’? Answer The following is an expression, with two uses of the comma operator: (the tra…
How can I avoid Array-callback-return error in my code
I want to filter through a list of items and display the items according to my filtered term. My list of items I have a input element that is a search field The search field has an onchange handler I am rendering the list items using .map helper method My state objects are as follows I want the ability to
refactoring assistance with reducing some array data objects in JavaScript
I need to reduce data in profiles array in a way such that the final object groups the data in profile obj based on the favorite movie and the users that liked/favorited the movie. I want something like: from the following data objects: I need some ideas in refactoring the following code for it to go back to …