TypeScript · Senior · Question 65 of 75

Why do excess property checks miss errors in this case?

const input = { name: 'A', nmae: 'typo' };
const user: User = input; // no error

✓Correct answer: Excess property checks apply only to fresh object literals, not to variables of a wider type
2TypeScript ignores typos
3User must be an interface for the check

Explanation

TypeScript has no exact object types. Assign literals directly, or use satisfies at the literal to keep the check.

Further reading

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