djbalinD
Convex Community•13mo ago•
9 replies
djbalin

Narrowing function return type

Hi, consider the toy example below: passing 
true
 as an argument causes the function to return a 
number
 while passing 
false
 causes it to return a boolean. The inferred return type is however always number | boolean regardless of what argument is passed.

I guess this is just a quirk with TS not narrowing function signature based on arguments passed. Is it possible to achieve this however in an elegant way? 🙂 

export const returnNumOrBool = authQuery({
  args: {
    returnNumber: v.boolean(),
  },
  handler: async (ctx, { returnNumber }) => {
    if (returnNumber === true) {
      return 1
    } else {
      return false
    }
  },
})
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