How to check if a string contains text from an array of substrings in JavaScript?

Pretty straight forward. In javascript, I need to check if a string contains any substrings held in an array. Answer There’s nothing built-in that will do that for you, you’ll have to write a function for it. If you know the strings don’t contain any of the characters that are special in regular expressions, then you can cheat a bit, like this: …which creates a regular expression that’s a series of alternations for the substrings you’re looking for (e.g., one|two) and tests to see if there are matches for any of them, but if any of the substrings contains any

How do you add multiple objects to an array? (JavaScript)

I’m not sure if I phrased the question right. I’m fairly new to JavaScript, and I’d like to add multiple objects (?) to an array. If I have this array: How would I add, say as to the same array? Sorry if this is a dumb question, but I really need an answer. Answer Items can be added to an array with the push method. Every array has this method build it, together with many other methods, and can be used to push a new value to the end of the array. In the push method create an object with

fetching specific object from array

In following example I am trying to get specific object from an array.First I am checking if it is there using find and after that getting only that object. Answer Fixed it in below snippet. Check it out.

How to update the quantity in my array in the local storage

I’m creating a shopping cart where in if I add to cart, the quantity should be added to the previous quantity. In my case it only sets to a quantity and is not adding. Here is the code that I tried: Answer Just needed a slight modification to the addition logic. You need to check if it already exists in the itemsInCart array before pushing it.

For Loop is Not Running Khan Academy Project:Bookshelf [closed]

Closed. This question needs details or clarity. It is not currently accepting answers. Want to improve this question? Add details and clarify the problem by editing this post. Closed 2 days ago. Improve this question “This program only displays one book. Make an array of books (at least two of them), and use a loop to display a row of them.” I want to use the for loop to draw the other book in the array. In the current state, i remains 0, and must be manually set to 1 to draw the next book. Answer Use a different variable

Auto complete as you type in JavaScript

I was looking the w3cschool link for auto complete as you type. The above only works for the first ordering for names eg. If country name is United States. You need to type Uni and it shows in drop-down. How to make it work if you type any letter eg ted or state so it still shows. United States in drop down. Answer All you need is do a includes string comparison instead of starts With and you should be all set if you just show the matching country instead f substring of matching text.

JavaScript: Diference in sorting behavior array of objects with keys by object property

I have two arrays with the same information but different keys. The keys of the first array are strings: The second array is indexed normally: If I try to sort them by age: In the end myOtherArray will be sorted but myArray will remain sorted by key. What am I missing here? Thanks! Answer Your first array does not actually contain any elements; you are treating it like an object by setting properties on it, which are ordered in insertion order except for numeric keys which are ordered in ascending order. You used the standard push method to add to

Updating Firestore Documents in Parallel Using Promise.all()

This question concerns the Firestore database, but, more generally, it concerns making async requests in parallel. Simply put, I wish to update multiple Firestore documents as quickly and efficiently as possible by mapping over an array of their document IDs. the .set() method is async (returning a promise) and so I understand that I can wrap the multiple requests – i.e. the map() – in a Promise.all() function, which will return a single promise once all of the requests have resolved. However, it is not at all clear to me whether I should await the set() within the map(). Whichever

Initialise an object with array properties

How can I initialise an object in JavaScript, the properties of which would be arrays? I want to have an object of this format: My usecase is the following: – When a property does not exist, create this property which should be an array and add a number. – When a property exists already, push the number to that array; this way I cannot initialise an array every time. What I’ve done so far is this: I am getting this error: Uncaught TypeError: Cannot read property ‘push’ of undefined which makes sense, as the property has not been initialised as

How to find biggest number in array around undefined elements?

My question is pretty simple actually but I couldnt find satisfied answer lets say that I have array like above.And I wanna get the max value in array which is 20. this is what I did but returned undefined so I tried something like that below and worked but filtering all undefined elements(iterating all) and then finding biggest element is big cost.I need something built-in js function such as Math.max.apply which can skip undefined elements and find the biggest value from array. Answer As far as I understand your question, I would like to answer it. I have an idea