perf: integrate nimma

[P0lip]

Closes #437, #506

Similarly to #1112, I'm going to extract a few unrelated changes to a separate PR.

Checklist

• Tests added / updated
• Docs added / updated

Does this PR introduce a breaking change?

• Yes
• No

Additional context

Introduces a totally different approach to JSON Path expression-based object lookup, leveraging nimma. Note - we still do rely on jsonpath-plus in certain circumstances, as nimma does not support the entire JSON Path syntax and all jsonpath-plus additions. The coverage is good enough, however, and almost the whole oas ruleset have expressions that can be optimized.
Currently, nimma is disabled by default and will be used only in Studio where performance is critical.
I'll enable it in future for everyone.
There are still a few changes left to make:

• $ref resolver - I've got a project that is slowly shaping up - once we switch to it, we should observe further improvements,
• oas2/oas3 schema rules are slow hogs,
• nimma itself could be optimized and have better coverage of JSON Path syntax.

Screenshots

openapi-directory/APIs/stripe.com/2019-09-09/swagger.yaml

This PR using nimma

5.4.0-beta1

5.4.0-beta1 with expensive rules disabled

---

openapi-directory/APIs/sendgrid.com/3.0/swagger.yaml

This PR using nimma

5.4.0-beta1

5.4.0-beta1 with expensive rules disabled

---

openapi-directory/APIs/adyen.com/**/*.yaml

This PR using nimma

5.4.0-beta1

5.4.0-beta1 with expensive rules disabled

---

openapi-directory/APIs/stoplight.io/api-v1/swagger.yaml

This PR using nimma

5.4.0-beta1

5.4.0-beta1 with expensive rules disabled

[nulltoken]

@P0lip Impressive gains! 👏

Currently, nimma is disabled by default and will be used only in Studio where performance is critical.
I'll enable it in future for everyone.

How about tweaking the tests so that they run twice, with and without Nimma?

[P0lip]

How about tweaking the tests so that they run twice, with and without Nimma?

Agree.
How do you feel about running suites twice? Once without Nimma, and once with Nimma.
Thinking of something as follows

"test": "jest && NIMMA=true jest"

[nulltoken]

How do you feel about running suites twice? Once without Nimma, and once with Nimma.
Thinking of something as follows

"test": "jest && NIMMA=true jest"

👍 I was thinking along those lines as well (as this dual setup is temporary).
Maybe also let karma know about this?

[marbemac]

Looks very promising!

[P0lip]

This should be good to go once #1184 is merged

[nulltoken]

@P0lip I know this is subject to debate, but I'd be in the camp of always adding braces.

[P0lip]

@nulltoken we can actually introduce some eslint rule.
I have no strong preference, but if you like curly braces, I'm all in for introducing the rule, so curly braces are always enforced.

[nulltoken]

@P0lip Minor refactoring proposal which should add to the jest and karma logs in which context the tests are being run. Thoughts?

diff --git a/jest.config.js b/jest.config.js
index ebb7d9e..047ff91 100644
--- a/jest.config.js
+++ b/jest.config.js
@@ -5,5 +5,6 @@ module.exports = {
   testMatch: ['<rootDir>/src/**/__tests__/*.(ts)'],
   testPathIgnorePatterns: ['/node_modules/', '\.karma\.test\.ts$'],
   coveragePathIgnorePatterns: ['<rootDir>/dist/', '/node_modules/'],
-  setupFilesAfterEnv: ['./setupJest.ts', './setupTests.ts']
+  setupFilesAfterEnv: ['./setupJest.ts', './setupTests.ts'],
+  globalSetup: '<rootDir>/setupJest.global.js',
 };
diff --git a/karma-jest.ts b/karma-jest.ts
index 9d5f656..5254988 100644
--- a/karma-jest.ts
+++ b/karma-jest.ts
@@ -1,5 +1,6 @@
 import { Expect } from 'expect/build/types';
 import * as JestMock from 'jest-mock';
+import { isNimmaEnvVariableSet } from './src/utils/isNimmaEnvVariableSet'
 
 declare var global: NodeJS.Global & {
   jest: typeof JestMock;
@@ -7,6 +8,8 @@ declare var global: NodeJS.Global & {
   test: jest.It;
 };
 
+console.info(`Nimma rule optimizer activated: ${isNimmaEnvVariableSet()}`);
+
 global.jest = require('jest-mock');
 global.expect = require('expect');
 global.test = it;
diff --git a/setupJest.global.js b/setupJest.global.js
new file mode 100644
index 0000000..71d2298
--- /dev/null
+++ b/setupJest.global.js
@@ -0,0 +1,7 @@
+'use strict';
+
+const isNimmaEnvVariableSet = require('./src/utils/isNimmaEnvVariableSet').isNimmaEnvVariableSet;
+
+module.exports = async () => {
+  console.info(`Nimma rule optimizer activated: ${isNimmaEnvVariableSet()}`);
+};
diff --git a/src/spectral.ts b/src/spectral.ts
index 3260531..6fb5881 100644
--- a/src/spectral.ts
+++ b/src/spectral.ts
@@ -33,6 +33,7 @@ import {
 import { IRuleset, RulesetExceptionCollection } from './types/ruleset';
 import { ComputeFingerprintFunc, defaultComputeResultFingerprint, empty } from './utils';
 import { generateDocumentWideResult } from './utils/generateDocumentWideResult';
+import { isNimmaEnvVariableSet } from './utils/isNimmaEnvVariableSet';
 
 memoize.Cache = WeakMap;
 
@@ -133,13 +134,7 @@ export class Spectral {
     empty(this.rules);
 
     for (const [name, rule] of Object.entries(rules)) {
-      if (
-        this.opts?.useNimma ||
-        (typeof global === 'object' && global?.process?.env?.USE_NIMMA) ||
-        // eslint-disable-next-line @typescript-eslint/ban-ts-ignore
-        // @ts-ignore, this is for Karma
-        (typeof window === 'object' && window?.__env__?.USE_NIMMA)
-      ) {
+      if (this.opts?.useNimma || isNimmaEnvVariableSet()) {
         try {
           this.rules[name] = new OptimizedRule(name, rule);
         } catch {
diff --git a/src/utils/isNimmaEnvVariableSet.ts b/src/utils/isNimmaEnvVariableSet.ts
new file mode 100644
index 0000000..736518a
--- /dev/null
+++ b/src/utils/isNimmaEnvVariableSet.ts
@@ -0,0 +1,11 @@
+export const isNimmaEnvVariableSet = (): boolean => {
+  const globalNimma = typeof global !== 'undefined' && typeof global === 'object' && Boolean(global?.process?.env?.USE_NIMMA);
+
+  // eslint-disable-next-line @typescript-eslint/ban-ts-ignore
+  // @ts-ignore
+  const windowNimma = typeof window !== 'undefined' && typeof window === 'object' && Boolean(window?.__env__?.USE_NIMMA);
+
+  const isNimmaActivated = globalNimma || windowNimma;
+
+  return Boolean(isNimmaActivated);
+};
-- 

[P0lip]

@nulltoken I like it!

[nulltoken]

‼️