Issue
When writing a try and catch block in TypeScript within Visual Studio Code, it’s common to encounter the error message “‘error’ is of type ‘unknown’” within the catch block.
Screenshot:
The image above showcases a basic example. When you hover over the word “error,” indicated by the red underline, a tooltip message appears
“‘error’ is of type ‘unknown’.ts(18046) var error: unknown”.
Solution Attempt
Simply assigning the type “Error” to the parameter “error” doesn’t resolve the issue.
Screenshot:
it gives another error message when hovering over the word “Error”, which is underlined in red:
‘Catch clause variable type annotation must be ‘any’ or ‘unknown’ if specified.ts(1196) interface Error’.
Solution
Add an if statement to check if error is an instance of Error.
const divide = (dividend: number, divider: number) => {
if (divider === 0) {
throw new Error('Divider must not be zero!')
}
return dividend / divider
}
try {
divide(5, 0)
} catch (error) {
if (error instanceof Error) {
console.log(error.message)
}
}It resolves the editor’s complaint! Hurray!