'Property does not exist on type 'never'
Solution 1:
if you write Component as React.FC, and using useState(),
just write like this would be helpful:
const [arr, setArr] = useState<any[]>([])
Solution 2:
Because you are assigning instance
to null
. The compiler infers that it can never be anything other than null
. So it assumes that the else block should never be executed so instance
is typed as never
in the else block.
Now if you don't declare it as the literal value null
, and get it by any other means (ex: let instance: Foo | null = getFoo();
), you will see that instance
will be null
inside the if block and Foo
inside the else block.
Never type documentation: https://www.typescriptlang.org/docs/handbook/basic-types.html#never
Edit:
The issue in the updated example is actually an open issue with the compiler. See:
https://github.com/Microsoft/TypeScript/issues/11498 https://github.com/Microsoft/TypeScript/issues/12176
Solution 3:
I had the same error and replaced the dot notation with bracket notation to suppress it.
e.g.:
obj.name -> obj['name']
Solution 4:
This seems to be similar to this issue: False "Property does not exist on type 'never'" when changing value inside callback with strictNullChecks
, which is closed as a duplicate of this issue (discussion): Trade-offs in Control Flow Analysis.
That discussion is pretty long, if you can't find a good solution there you can try this:
if (instance == null) {
console.log('Instance is null or undefined');
} else {
console.log(instance!.name); // ok now
}
Solution 5:
if you're receiving the error in parameter, so keep any
or any[]
type of input like below
getOptionLabel={(option: any) => option!.name}
<Autocomplete
options={tests}
getOptionLabel={(option: any) => option!.name}
....
/>