type Scores = Record<string, number>
const scores: Scores = { alice: 95, bob: 87 }Record<K, V> constructs an object type whose keys are K and whose values are all V.
Record<K, V> creates an object type with keys of type K and values of type V.
Challenge: Implement buildRecord<K extends string, V>(keys: K[], value: V): Record<K, V> that creates an object mapping every key to value.
buildRecord(['a', 'b', 'c'], 0) // → { a: 0, b: 0, c: 0 }