Improve validation

src/report/formats/detect.js

@@ -26,11 +26,11 @@ export const computeFormat = function ({ config: { output } }) {
   return format
 }
 
-// Validate that a reporter supports the format specified by a given `output`
-export const validateFormat = function (
-  format,
+// Validate that a reporter supports the `format` specified by a given `output`
+export const validateOutputFormat = function (
+  output,
   {
-    config: { output },
+    config: { format },
     context: {
       plugin,
       plugin: { id },
@@ -43,7 +43,7 @@ export const validateFormat = function (
 
   if (!hasMethod) {
     throw new Error(
-      `must not use unsupported "output: ${output}" with reporter "${id}".`,
+      `uses a file extension or format not supported by the reporter "${id}".`,
     )
   }
 }

src/report/reporters/top_definitions.js

@@ -1,4 +1,4 @@
-import { computeFormat, validateFormat } from '../formats/detect.js'
+import { computeFormat, validateOutputFormat } from '../formats/detect.js'
 import { isTtyOutput } from '../tty.js'
 
 // Reporter-specific definitions of top-level properties
@@ -25,7 +25,10 @@ export const reportersTopDefinitions = [
   {
     name: 'format',
     compute: computeFormat,
-    validate: validateFormat,
+  },
+  {
+    name: 'output',
+    validate: validateOutputFormat,
   },
   // `reporter.config.tty` is `true` when output is interactive terminal.
   // Several reporter's configuration properties default to `true` only when