Precompile Ajv Blueprint validator to avoid CSP issues (#1649)

## Motivation for the change, related issues

[The Chrome Content Security
Policy](https://developer.chrome.com/docs/privacy-security/csp) doesn't
allow the use of eval and new Function.

This prevents people from building Chrome extensions that interact with
Playground.

This PR is an alternative to #1647 and exists because the jsonschema
library used by that PR did not generate user-friendly validation
errors. Also, if we can stick with our current validation library, we
might as well because it is more well-tested in the context of
Playground.

Fixes #1641

## Implementation details

This PR precompiles an Ajv-based Blueprint JSON validator to avoid CSP
issues as suggested in the Ajv docs
[here](https://github.com/ajv-validator/ajv/blob/9050ba1359fb87cd7c143f3c79513ea7624ea443/docs/security.md#content-security-policy).

## Testing Instructions (or ideally a Blueprint)

CI: unit tests and e2e tests

packages/playground/blueprints/.eslintrc.json

@@ -1,6 +1,6 @@
 {
 	"extends": ["../../../.eslintrc.json"],
-	"ignorePatterns": ["!**/*"],
+	"ignorePatterns": ["!**/*", "blueprint-schema-validator.js"],
 	"overrides": [
 		{
 			"files": ["*.ts", "*.tsx", "*.js", "*.jsx"],

packages/playground/blueprints/bin/generate-schema.js

@@ -1,5 +1,8 @@
 import tsj from 'ts-json-schema-generator';
 import fs from 'fs';
+import Ajv from 'ajv';
+import ajvStandaloneCode from 'ajv/dist/standalone/index.js';
+import prettier from 'prettier';
 
 /** @type {import('ts-json-schema-generator/dist/src/Config').Config} */
 const config = {
@@ -11,6 +14,8 @@ const config = {
 
 const output_path =
 	'packages/playground/blueprints/public/blueprint-schema.json';
+const validator_output_path =
+	'packages/playground/blueprints/public/blueprint-schema-validator.js';
 
 const maxRetries = 2;
 async function exponentialBackoff(callback, retries = 0, delay = 1000) {
@@ -58,6 +63,22 @@ const schemaString = JSON.stringify(schema, null, 2)
 	// Naively remove TypeScript generics <T> from the schema:
 	.replaceAll(/%3C[a-zA-Z]+%3E/g, '')
 	.replaceAll(/<[a-zA-Z]+>/g, '');
-fs.writeFile(output_path, schemaString, (err) => {
-	if (err) throw err;
+fs.writeFileSync(output_path, schemaString);
+
+const ajv = new Ajv({
+	discriminator: true,
+	code: {
+		source: true,
+		esm: true,
+	},
 });
+const validate = ajv.compile(schema);
+const rawValidationCode = ajvStandaloneCode(ajv, validate);
+
+// Use prettier to make the generated validation code more readable.
+const prettierConfig = JSON.parse(fs.readFileSync('.prettierrc', 'utf8'));
+const formattedValidationCode = prettier.format(
+	rawValidationCode,
+	prettierConfig
+);
+fs.writeFileSync(validator_output_path, formattedValidationCode);

packages/playground/blueprints/public/blueprint-schema-validator.d.ts

@@ -0,0 +1,2 @@
+import type { ValidateFunction } from 'ajv';
+export default BlueprintValidateFunction as ValidateFunction;