I’m trying to loop through the counties object of object and add two new properties(nameCombined & codeCombined) to the existing Keys (Bucks and Montgomery) I got up till here. But not able to mutate 🙁 Here is the Data: Expected Result: Answer You were on the right path with entries and forEach, but if yo…
Tag: ecmascript-6
In JS ES6, why is it that if I export default, then I cannot export it individually?
I found that I can do: but I cannot move that default to the top: Why is that? They just seem to serve the same purpose: export Foo as default and individually, but the first form is ok while the second form is not. Answer I can’t quite tell if this is a language quirk, because I never see a
sorting a list alphabetically is not sorting anything at all
I’m trying to take a list of cars and sort them alphabetically. So I found this method to sort: But when I write it out to the console, you can see the results below and they are not alphabetically sorted. What could I be doing wrong? Thanks! Answer Your log seems to imply that this data is from immutab…
How to remove event callback with parameters
I have a web application that page A has video, and page B doesn’t. The video has the onended event when it finishes video playback. I tried to remove the event before the component unmounts with removeEventListener, or the video ended event will be fired after I switched to page B. However, I cannot fi…
Typescript – type ‘string’ can’t be used to index type
I’m using Vue.js with TypeScript and have run into some errors when using dynamic object keys. Here is my function: Here are the errors that I get: I’m not entirely sure what the issue is as I have defined the interface ResetStateItems and thought I could just use keyof to make it work? Answer Ins…
ReactJS – unable to show stuff on the DOM that is in another component
Hi there I’m a beginner looking for some help. I have made two .js files. One is the App.js and another is a Box component. This is App.js This is my BoxComponent However, for some reason, the paragraphs and input within the boxComp doesn’t render onto the DOM and I can’t seem to figure out …
Extending Promise base class typings
I am trying to extend Promise base class, with a static method and an instance method. I am having trouble with the typescript definitions. See my code below! With this code, when I try to defined Promise.timeout above, typescript gives me the error : Property timeout is a static member of type PromiseConstru…
How to increase all values of a map in javascript
I have this map: And I want to add this new key/value: How can I increase the values of all the old map elements in 1? So I get the following map: Answer You can use something like this:
Babel with Internet Explorer
Why isn’t this working in IE11 ? I was under the impression that Babel will automatically convert new-style code to old-style. Is there some configuration setup to be done ? Answer Babel can transform language features from newer versions of JavaScript into equivalents in older versions. It can’t …
How to compare an array of objects with an array of strings?
How to compare these arrays? I want to compare and get a result like the below. Array of string Array of object As you can see there is no Sliders categoryName in the array of string. I expected the result should be another array of objects. As the following Thanks! Answer You can use .filter as follows: