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- /**
- * Helper function for exhaustive checks of discriminated unions.
- * https://basarat.gitbooks.io/typescript/docs/types/discriminated-unions.html
- *
- * @example
- *
- * type A = {type: 'a'};
- * type B = {type: 'b'};
- * type Union = A | B;
- *
- * function doSomething(arg: Union) {
- * if (arg.type === 'a') {
- * return something;
- * }
- *
- * if (arg.type === 'b') {
- * return somethingElse;
- * }
- *
- * // TS will error if there are other types in the union
- * // Will throw an Error when called at runtime.
- * // Use `assertNever(arg, true)` instead to fail silently.
- * return assertNever(arg);
- * }
- */
- export function assertNever(value: never, noThrow?: boolean): never {
- if (noThrow) {
- return value
- }
- throw new Error(
- `Unhandled discriminated union member: ${JSON.stringify(value)}`,
- );
- }
- export default assertNever;
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