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wesbos/non-empty-string.ts

Last active November 4, 2022 14:00
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non-empty-string.ts
// Here we check if our custom type "Stringy" extends a narrow type of ''
// If it does, the type is never
// If it doesnt, the type is "Strinfy", which is just a string type
function getItem<Stringy extends string>(
id: Stringy extends '' ? never : Stringy
) {
// code here
}
// works:
getItem('abc123'); // No error
// Error
getItem('');
getItem();
getItem(123); // fail
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