feat(core): Added new method getEnvVarOnDemandStrict to throw error for unset env vars

ts/qenv.classes.qenv.ts

@@ -111,6 +111,21 @@ export class Qenv {
     }
   }
 
+  /**
+   * Like getEnvVarOnDemand, but throws an error if the env var is not set.
+   * @param envVarNameOrNames 
+   * @returns 
+   */
+  public async getEnvVarOnDemandStrict(
+    envVarNameOrNames: TEnvVarRef | TEnvVarRef[]
+  ): Promise<string> {
+    const value = await this.getEnvVarOnDemand(envVarNameOrNames);
+    if (!value) {
+      throw new Error(`Env var ${envVarNameOrNames} is not set!`);
+    }
+    return value;
+  }
+
   public getEnvVarOnDemandSync(envVarNameOrNames: string | string[]): string | undefined {
     console.warn('requesting env var sync leaves out potentially important async env sources.');