There’s no casting in javascript, so you cannot throw if “casting fails”.Typescript supports casting but that’s only for compilation time, and you can do it like this: You can check at runtime if the value is valid and if not throw an error, i.e.: Edit As @huyz pointed out, there’s no need for the type assertion because isToDoDto is … Read more
When can a certain object be cast into another object? Does the casted object have to be a subtype of the other object? I’m trying to figure out the rules… Edit: I realized that I didn’t explain my issue at all: basically I am casting an object to an interface type. However, at run-time, I … Read more
Why this is not possible: Because String and Integer are not in the same Object hierarchy. The casting which you are trying, works only if they are in the same hierarchy, e.g. In this case, (A) objB or (Object) objB or (Object) objA will work. Hence as others have mentioned already, to convert an integer to string use: String.valueOf(integer), or Integer.toString(integer) for primitive, … Read more
From MySQL docs: Fixed-Point Types (Exact Value) – DECIMAL, NUMERIC: In standard SQL, the syntax DECIMAL(M) is equivalent to DECIMAL(M,0) So, you are converting to a number with 2 integer digits and 0 decimal digits. Try this instead:
From the .NET reference source: So, your answer is that they are exactly the same, under the hood. Any preference between the two is strictly a personal style choice. Personally, I would always use the cast as it is shorter and and just seems more idiomatic to me.
It’s not obvious what you’re trying to accomplish here, but I’ll assume you’re trying to do some pointer arithmetic with x, and would like x to be an integer for this arithmetic but a void pointer on return. Without getting into why this does or doesn’t make sense, you can eliminate the warning by explicitly … Read more
When you do the second one, you’re making a new arraylist, you’re not trying to pretend the other list is an arraylist. I mean, what if the original list is implemented as a linkedlist, or some custom list? You won’t know. The second approach is preferred if you really need to make an arraylist from … Read more
From String to Date From Date to String
The problem is that when the type is inferred, then the type of o is: That’s not the same as { dic: { [name: string]: number } }. Critically, with the top signature you’re not allowed to do something like o.dic[‘x’] = 1. With the 2nd signature you are. They are equivalent types at runtime (indeed, they’re the exact … Read more