Jest equivalent to RSpec lazy evaluated variables (let)?

In rspec you can do something like this: This allows you to define a method call or instantiation of a large object as a sum of its smaller parts. You can then override those individual small parts inside different contexts. The idea being that you create a happy path before each test, and then specify deviations from the happy path within your context blocks. Unfortunately, I can’t seem to do this with Jest. I’ve tried the following: Because jest executes every describe block before running any specific describe block, input is always ‘baz’. Does anyone know a work around, or

ECMAScript 6 spread syntax in object deconstruction. Support in TypeScript and Babel

Is the following valid ECMAScript 6? It seems to be supported by the latest version of Babel but it isn’t by TypeScript. I couldn’t find any ES6 references dealing with this case. Answer No, this is not valid ECMAScript 6. ES6 does only support rest syntax in function parameters and array destructuring, and spread syntax in function calls and array construction. It seems to be supported by the latest version of Babel Babel does implement the objectRestSpread ES7 proposal as a experimental plugin. You shouldn’t use this feature, it may break at any time.

Group results of multiple POST API calls

I use the below script to loop through the input (skipping first one) to post some data to my API. Result How can I capture the combined response of both calls into a variable I can use later on in my script? something like var allNum = res.result.number[0]? This is what I want -> Var allTens = “002, 003″ Script Answer You can declare a variable outside of the .forEach Call that could be used within that “scope”. This variable can just be an array that you append the results to:

How can I create a hook that reacts to an event to load more data?

I am trying to create a functionality where if a user clicks on a LOAD MORE button, it returns more data. I already have some code done but every time I click on the LOAD MORE button, it removes the first 12 items and sets the new 12 items, but I don’t want that, I want to keep the 12 old tems, It is just a regular load more functionality. Besides that, I need to turn this into a hook which I am going to using across the whole application. What am I missing? Any ideas? Answer You do not

ES6 Classes: Bind “this” to nested functions

I have multiple nested functions in a ES6 Class. Now I wonder how I can easily bind this of the class instance to all the subfunctions. I know of… …but it feels like an awkward solution for multiple nested functions. Does anyone know of a more elegant solution? Answer You can use arrow functions. They work in rather a similar manner. The arrow notation will replace this with the value of the context of the arrow function’s scope.

Iterate through array and call data function from loop

The follow should return 3 different results depending on the array value as it iterates through. I think this question is correct, how can I change it so data{} is a function called from my loop and so a new set of data is posted each time? (difference is the array value) I’m not sure how I would do this so that the value matches and changes accordingly. I have a switch included because my API doesn’t like the format of the input so have to change it. Not even sure this is the best approach so any advice is

destructing es6 in array push

i want to use something like destructing assignment in ES6 for having cleaner code but i dont know how to use it in something like pushing in array or anyway can is use it or something similar?. this sample code is in vue js: Answer Try this code: or this: And then you can remove unnecessary words, like this:

Getting error while referencing the type as index

I have an array of objects with the following structure I need to take each key within each object inside array and form an array out of it. Basically grouping based on the key present in all the objects.If the object has no “values” it should return 0 across the val1,val2,val3. Here I am passing an string, that will be used inside reduce.I am getting this error any cannot be used as index whenever I pass in a dynamically string that will be used inside a reduce function whenever typescript is enabled. The code works just fine, but after I

Why EventTarget subclass instances lose their names?

The current version of JavaScript implements EventTarget as a class instead of an interface, so you can create an instance of EventTarget with all the expected methods. I tried to copy/paste the EventTarget example in the console (on both Chrome and Firefox) but when I inspect the myEventTarget object (that is build as a subclass of EventTarget named MyEventTarget), the console says that myEventTarget is an EventTarget, not a MyEventTarget. This is the code Why the console says that myEventTarget is just an EventTarget? I found this thing quite uncommon because if I type the following code the console says

how to put a file in state variable with react hooks

I’m trying to upload a picture using react hooks however I’m getting the following error: when I change the onChangePicture to the picture variable is undefined, any help would be appreciated. Answer I think you meant to do: This will concatenate the first file to all current files. Remember to use const [picture, setPicture] = useState([]); as to make sure it doesn’t break the first time around