API Reference / @evolu/common / Function / exhaustiveCheck

Function: exhaustiveCheck()

function exhaustiveCheck(value): never;

Defined in: packages/common/src/Function.ts:30

Helper function to ensure exhaustive matching in a switch statement. Throws an error if an unhandled case is encountered.

Remember, it's useful only when we don't return anything from the switch statement. Otherwise, a return type of a function is enough.

Example

type Color = "red" | "green" | "blue";

function handleColor(color: Color): void {
  switch (color) {
    case "red":
      console.log("Handling red");
      break;
    case "green":
      console.log("Handling green");
      break;
    case "blue":
      console.log("Handling blue");
      break;
    default:
      exhaustiveCheck(color); // Ensures all cases are handled
  }
}

Parameters

Parameter	Type
`value`	`never`

Returns

never