[Tests] parsers.all: improve min ecmaVersion logic

tests/helpers/parsers.js

@@ -2,6 +2,7 @@
 
 const path = require('path');
 const semver = require('semver');
+const entries = require('object.entries');
 const version = require('eslint/package.json').version;
 const flatMap = require('array.prototype.flatmap');
 const tsParserVersion = require('@typescript-eslint/parser/package.json').version;
@@ -10,6 +11,25 @@ const disableNewTS = semver.satisfies(tsParserVersion, '>= 4.1') // this rule is
   ? (x) => Object.assign({}, x, { features: [].concat(x.features, 'no-ts-new') })
   : (x) => x;
 
+function minEcmaVersion(features, parserOptions) {
+  const minEcmaVersionForFeatures = {
+    'class fields': 2022,
+    'optional chaining': 2020,
+  };
+  const result = Math.max.apply(
+    Math,
+    [].concat(
+      (parserOptions && parserOptions.ecmaVersion) || [],
+      flatMap(entries(minEcmaVersionForFeatures), (entry) => {
+        const f = entry[0];
+        const y = entry[1];
+        return features.has(f) ? y : [];
+      })
+    ).map((y) => (y > 5 && y < 2015 ? y + 2009 : y)) // normalize editions to years
+  );
+  return Number.isFinite(result) ? result : undefined;
+}
+
 const NODE_MODULES = '../../node_modules';
 
 const parsers = {
@@ -58,7 +78,7 @@ const parsers = {
       const features = new Set([].concat(test.features || []));
       delete test.features;
 
-      const es = features.has('class fields') ? 2022 : (features.has('optional chaining') ? 2020 : (test.parserOptions && test.parserOptions.ecmaVersion) || undefined); // eslint-disable-line no-nested-ternary
+      const es = minEcmaVersion(features, test.parserOptions);
 
       function addComment(testObject, parser) {
         const extras = [].concat(
@@ -133,10 +153,8 @@ const parsers = {
 
       return [].concat(
         skipBase ? [] : addComment(
-          Object.assign({}, test, typeof es !== 'undefined' && {
-            parserOptions: Object.assign({}, test.parserOptions, {
-              ecmaVersion: Math.max((test.parserOptions && test.parserOptions.ecmaVersion) || 0, es),
-            }),
+          Object.assign({}, test, typeof es === 'number' && {
+            parserOptions: Object.assign({}, test.parserOptions, { ecmaVersion: es }),
           }),
           'default'
         ),