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export function exactlyOne<T>(input: ReadonlyArray<T>, property: string): T {
if (input.length !== 1) {
throw new Error(
`Expected exactly one element for ${property}, got ${input.length}`
);
}
return input[0];
}
export function optionalOne<T>(
input: ReadonlyArray<T>,
property: string
): T | undefined {
if (input.length > 1) {
throw new Error(
`Expected one optional element for ${property}, got ${input.length}`
);
}
return input[0];
}
export function required<T>(
input: T | undefined,
property: string
): NonNullable<T> {
if (input == null) {
throw new Error(`Expected a value for ${property}, got undefined`);
}
return input;
}
export function allRequired<T>(
input: ReadonlyArray<T | undefined>,
property: string
): Array<NonNullable<T>> {
return input.map((v, i) => required(v, `${property}[${i}]`));
}
export function atLeastOne<T>(
input: ReadonlyArray<T>,
property: string
): ReadonlyArray<T> {
if (input.length === 0) {
throw new Error(`Expected at least one element for ${property}`);
}
return input;
}
export function atLeastOneAndAllRequired<T>(
input: ReadonlyArray<T | undefined>,
property: string
): ReadonlyArray<NonNullable<T>> {
return atLeastOne(allRequired(input, property), property);
}
export function valueForKey<T>(input: Record<string, T>, key: string): T {
return required(input[key], key);
}
export function valuesForKeys<T>(
input: Record<string, T>,
keys: string[]
): T[] {
return keys.map((key) => valueForKey(input, key));
}
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