20 lines
475 B
TypeScript
20 lines
475 B
TypeScript
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export type NotNull<T> = T extends null ? never : T;
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export type Nullable<T> = T | null;
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function isNotNull<T>(input: Nullable<T>): input is NotNull<T> {
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return input !== null;
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}
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function expectNotNull<T>(input: Nullable<T>, msg: string): NotNull<T> {
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if (isNotNull(input)) {
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return input;
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}
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throw new TypeError(msg);
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}
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export function unwrapNullable<T>(input: Nullable<T>): NotNull<T> {
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return expectNotNull(input, `unwrapping \`null\``);
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}
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