perf: improve ruleset loading

src/rulesets/mergers/formats.ts

@@ -1,6 +1,6 @@
 import { RuleCollection } from '../../types';
 
-export function mergeFormats(rules: RuleCollection, formats: string[]) {
+export function mergeFormats(rules: RuleCollection, formats: string[]): void {
   if (formats.length > 0) {
     for (const rule of Object.values(rules)) {
       if (typeof rule === 'object' && rule.formats === void 0) {

src/rulesets/mergers/functions.ts

@@ -8,7 +8,7 @@ export function mergeFunctions(
   target: RulesetFunctionCollection,
   source: RulesetFunctionCollection,
   rules: RuleCollection,
-) {
+): void {
   const map: Dictionary<string, string> = {};
 
   for (const [name, def] of Object.entries(source)) {

src/rulesets/mergers/rules.ts

@@ -1,6 +1,5 @@
 import { DiagnosticSeverity } from '@stoplight/types';
-import { cloneDeep } from 'lodash';
-import { HumanReadableDiagnosticSeverity, IRule } from '../../types';
+import { HumanReadableDiagnosticSeverity, IRule, IThen } from '../../types';
 import { FileRule, FileRuleCollection, FileRulesetSeverity } from '../../types/ruleset';
 import { DEFAULT_SEVERITY_LEVEL, getDiagnosticSeverity, getSeverityLevel } from '../severity';
 import { isValidRule } from '../validation';
@@ -37,7 +36,7 @@ export function mergeRules(
 
 const ROOT_DESCRIPTOR = Symbol('root-descriptor');
 
-function markRule(rule: IRule) {
+function markRule(rule: IRule): void {
   if (!(ROOT_DESCRIPTOR in rule)) {
     Object.defineProperty(rule, ROOT_DESCRIPTOR, {
       configurable: false,
@@ -48,7 +47,7 @@ function markRule(rule: IRule) {
   }
 }
 
-function updateRootRule(root: IRule, newRule: IRule | null) {
+function updateRootRule(root: IRule, newRule: IRule | null): void {
   markRule(root);
   Object.assign(root[ROOT_DESCRIPTOR], copyRule(newRule === null ? root : Object.assign(root, newRule)));
 }
@@ -57,11 +56,23 @@ function getRootRule(rule: IRule): IRule | null {
   return rule[ROOT_DESCRIPTOR] !== undefined ? rule[ROOT_DESCRIPTOR] : null;
 }
 
-function copyRule(rule: IRule) {
-  return cloneDeep(rule);
+function copyRuleThen(then: IThen): IThen {
+  return {
+    ...then,
+    ...('functionOptions' in then ? { ...then.functionOptions } : null),
+  };
 }
 
-function processRule(rules: FileRuleCollection, name: string, rule: FileRule | FileRulesetSeverity) {
+function copyRule(rule: IRule): IRule {
+  return {
+    ...rule,
+    ...('then' in rule
+      ? { then: Array.isArray(rule.then) ? rule.then.map(copyRuleThen) : copyRuleThen(rule.then) }
+      : null),
+  };
+}
+
+function processRule(rules: FileRuleCollection, name: string, rule: FileRule | FileRulesetSeverity): void {
   const existingRule = rules[name];
 
   switch (typeof rule) {
@@ -116,7 +127,7 @@ function processRule(rules: FileRuleCollection, name: string, rule: FileRule | F
   }
 }
 
-function normalizeRule(rule: IRule, severity: DiagnosticSeverity | HumanReadableDiagnosticSeverity | undefined) {
+function normalizeRule(rule: IRule, severity: DiagnosticSeverity | HumanReadableDiagnosticSeverity | undefined): void {
   if (rule.recommended === void 0) {
     rule.recommended = true;
   }

src/rulesets/reader.ts

@@ -1,6 +1,6 @@
 import { Cache } from '@stoplight/json-ref-resolver';
 import { ICache } from '@stoplight/json-ref-resolver/types';
-import { join } from '@stoplight/path';
+import { extname, join } from '@stoplight/path';
 import { Optional } from '@stoplight/types';
 import { parse } from '@stoplight/yaml';
 import { readFile, readParsable } from '../fs/reader';
@@ -15,6 +15,14 @@ export interface IRulesetReadOptions {
   timeout?: number;
 }
 
+function parseContent(content: string, source: string): unknown {
+  if (extname(source) === '.json') {
+    return JSON.parse(content);
+  }
+
+  return parse(content);
+}
+
 export async function readRuleset(uris: string | string[], opts?: IRulesetReadOptions): Promise<IRuleset> {
   const base: IRuleset = {
     rules: {},
@@ -54,18 +62,19 @@ const createRulesetProcessor = (
 
     processedRulesets.add(rulesetUri);
     const { result } = await httpAndFileResolver.resolve(
-      parse(
+      parseContent(
         await readParsable(rulesetUri, {
           timeout: readOpts?.timeout,
           encoding: 'utf8',
         }),
+        rulesetUri,
       ),
       {
         baseUri: rulesetUri,
         dereferenceInline: false,
         uriCache,
         async parseResolveResult(opts) {
-          opts.result = parse(opts.result);
+          opts.result = parseContent(opts.result, opts.targetAuthority.pathname());
           return opts;
         },
       },

src/rulesets/validation.ts

@@ -9,7 +9,7 @@ import { IFunction, IFunctionPaths, IFunctionValues, IRule, JSONSchema } from '.
 const ajv = new AJV({ allErrors: true, jsonPointers: true });
 const validate = ajv.addSchema(ruleSchema).compile(rulesetSchema);
 
-const serializeAJVErrors = (errors: AJV.ErrorObject[]) =>
+const serializeAJVErrors = (errors: AJV.ErrorObject[]): string =>
   errors.map(({ message, dataPath }) => `${dataPath} ${message}`).join('\n');
 
 export class ValidationError extends AJV.ValidationError {