minor improvement of 'assertUnreachable', contributed 'assertCondition' to error.ts (#1940)

sailingKieler · web-flow · commit a317db05e27f · 2025-05-26T13:29:09.000+02:00
diff --git a/packages/langium/src/utils/errors.ts b/packages/langium/src/utils/errors.ts
@@ -12,6 +12,12 @@ export class ErrorWithLocation extends Error {
     }
 }
 
-export function assertUnreachable(_: never): never {
-    throw new Error('Error! The input value was not handled.');
+export function assertUnreachable(_: never, message = 'Error: Got unexpected value.'): never {
+    throw new Error(message);
+}
+
+export function assertCondition(condition: boolean, message: string = 'Error: Condition is violated.'): asserts condition {
+    if (!condition) {
+        throw new Error(message);
+    }
 }

Original file line number	Diff line number	Diff line change
`@@ -12,6 +12,12 @@ export class ErrorWithLocation extends Error {`
`12`	`12`	`}`
`13`	`13`	`}`
`14`	`14`
`15`		`-export function assertUnreachable(_: never): never {`
`16`		`- throw new Error('Error! The input value was not handled.');`
	`15`	`+export function assertUnreachable(_: never, message = 'Error: Got unexpected value.'): never {`
	`16`	`+ throw new Error(message);`
	`17`	`+}`
	`18`	`+`
	`19`	`+export function assertCondition(condition: boolean, message: string = 'Error: Condition is violated.'): asserts condition {`
	`20`	`+ if (!condition) {`
	`21`	`+ throw new Error(message);`
	`22`	`+ }`
`17`	`23`	`}`