Operands of '+' operation must either be both strings or both numbers. Consider using a template literal @typescript-eslint/restrict-plus-operands

Question

I just using tslint but this block of code throws me a error.

 const MemberNumber = 'MBR' + pinCode + sliceNumber

Operands of '+' operation must either be both strings or both numbers. Consider using a template literal  @typescript-eslint/restrict-plus-operands

I tired with template method again throwing the tslint error.

const MemberNumber = `MBR${pinCode}${sliceNumber}`

 Invalid type "any" of template literal expression  @typescript-eslint/restrict-template-expres

how to fix this.

Thanks

Styracaceous

Can you show where pinCode and sliceNumber are defined? – Mobster

pincode and sliceNumber both are string. – Styracaceous

I am not convinced - can you include the code where they're defined? – Mobster

const pinCode = "600028" const sliceNumber = "887277272" – Styracaceous

Answer 1

It looks like pinCode or sliceNumber is of type number, so converting it to a string should work:

const MemberNumber = `MBR${String(pinCode)}${String(sliceNumber)}`

Tia

Thanks a lot. You've saved me from hours of frustration. You're the man. – Caldarium

Answer 2

you can convert pinCode and sliceNumber as string

const MemberNumber = MBR${pinCode as string}${sliceNumber as string};

Inexpressive

Answer 3

Typescript does not cast numbers to string implicitly, so you should cast to string first and then you can make concatenation with string. One or more of your parameters may be number.

This will fix your issue:

const MemberNumber = `MBR${String(pinCode)}${String(sliceNumber)}`

Dropper

Sure wish I could understand why TF Angular 15 is making me cast a string to a String!? – Schoolmaster