error TS2363: The right-hand side of an arithmetic operation must be of type 'any', 'number' or an enum type.

[SomeKittens]

I have the following code:

var blockLen = ecb.determineBlockSize();

var len = ecb.encrypt(Buffer.concat([mysteryBytes, mysteryBuffer])).length;

console.log(len, len/blockLen);

The signature of ecb.determineBlockSize is determineBlockSize (): Number {

However, I get an error on the console.log telling me that:

error TS2363: The right-hand side of an arithmetic operation must be of type 'any', 'number' or an enum type.

The return type is Number, the typeof reveals number, yet I still get this error.

tsc --version
message TS6029: Version 1.5.0-alpha

[DanielRosenwasser]

Can you declare the return type of determineBlockSize as number instead of Number?

[SomeKittens]

I don't get the error with number - what's the difference?

[DanielRosenwasser]

The short version is that you should always be returning number instead of Number, string instead of String, boolean instead of Boolean, and usually almost anything else instead of Object (Note the casing for each name.)

---

In TypeScript, we have several primitive types like number, string, and boolean. They describe the type of values like 100.0, "hello", and true respectively. Their behavior with operators is as it's been defined in the specification. However, to determine whether a property access on them is valid (i.e. whether in the expression foo.x, it's valid to grab x off of foo), we get their apparent types, which are dependent on the interfaces Number, String and Boolean in lib.d.ts. These interfaces exist mainly to serve the apparent types of these primitives.

From the TypeScript spec:

For purposes of determining type relationships (section 3.10) and accessing properties (section 4.10), the Number primitive type behaves as an object type with the same properties as the global interface type 'Number'.

[SomeKittens]

Ah, thanks. Misread the headings under "Basic Types" (which are capitalized) as the correct way to do things. Now seeing the code examples are lowercase.

[chanakaDe]

I also get the same issue here.
user_checking(registerdata, tested_users):boolean {
return registerdata.userid && typeof tested_users[registerdata.userid] == 'undefined';
}
can anyone tell me how to fix ?