feat(apidom): add support for transforming ApiDOM into S-expressions

apidom/packages/apidom/src/index.ts

@@ -111,3 +111,5 @@ export const toString = (
   const refract = dehydrate(element, namespace);
   return JSON.stringify(refract);
 };
+
+export { default as sexprs } from './sexprs';

apidom/packages/apidom/src/sexprs.ts

@@ -0,0 +1,34 @@
+import stampit from 'stampit';
+import { Element } from 'minim';
+
+import { visit } from './traversal/visitor';
+
+const SymbolicExpressionsVisitor = stampit({
+  props: {
+    nestingLevel: 0,
+    result: '',
+  },
+  methods: {
+    enter(element: Element) {
+      const { element: elementName } = element;
+      const capitalizedElementName = elementName.charAt(0).toUpperCase() + elementName.slice(1);
+      const indent = '  '.repeat(this.nestingLevel);
+      this.result += this.nestingLevel > 0 ? '\n' : '';
+      this.result += `${indent}(${capitalizedElementName}Element`;
+      this.nestingLevel += 1;
+    },
+    leave() {
+      this.nestingLevel -= 1;
+      this.result += ')';
+    },
+  },
+});
+
+// transforms ApiDOM into S-expressions (Symbolic Expressions)
+const sexprs = (element: Element): string => {
+  const visitor = SymbolicExpressionsVisitor();
+  visit(element, visitor);
+  return visitor.result;
+};
+
+export default sexprs;

apidom/packages/apidom/test/sexprs.ts

@@ -0,0 +1,95 @@
+import { assert } from 'chai';
+import { ObjectElement } from 'minim';
+import dedent from 'dedent';
+import { trim } from 'ramda';
+import { InfoElement } from 'apidom-ns-openapi-3-1';
+
+import sexprs from '../src/sexprs';
+
+describe('sexprs', function () {
+  context('given generic ApiDOM', function () {
+    specify('should transform into S-expressions', function () {
+      const genericObj = new ObjectElement({
+        a: 1,
+        b: true,
+        c: ['a', null],
+      });
+      const expected = trim(dedent`
+        (ObjectElement
+          (MemberElement
+            (StringElement)
+            (NumberElement))
+          (MemberElement
+            (StringElement)
+            (BooleanElement))
+          (MemberElement
+            (StringElement)
+            (ArrayElement
+              (StringElement)
+              (NullElement))))`);
+
+      assert.strictEqual(sexprs(genericObj), expected);
+    });
+  });
+
+  context('given semantic ApiDOM', function () {
+    specify('should transform into S-expressions', function () {
+      const semanticObj = InfoElement.refract({
+        title: 'title',
+        summary: 'summary',
+        description: 'description',
+        contact: {
+          name: 'name',
+          url: 'url',
+          email: 'email',
+        },
+        license: {
+          name: 'name',
+          identifier: 'identifier',
+          url: 'url',
+        },
+        version: '1.0.0',
+      });
+      const expected = trim(dedent`
+        (InfoElement
+          (MemberElement
+            (StringElement)
+            (StringElement))
+          (MemberElement
+            (StringElement)
+            (StringElement))
+          (MemberElement
+            (StringElement)
+            (StringElement))
+          (MemberElement
+            (StringElement)
+            (ContactElement
+              (MemberElement
+                (StringElement)
+                (StringElement))
+              (MemberElement
+                (StringElement)
+                (StringElement))
+              (MemberElement
+                (StringElement)
+                (StringElement))))
+          (MemberElement
+            (StringElement)
+            (LicenseElement
+              (MemberElement
+                (StringElement)
+                (StringElement))
+              (MemberElement
+                (StringElement)
+                (StringElement))
+              (MemberElement
+                (StringElement)
+                (StringElement))))
+          (MemberElement
+            (StringElement)
+            (StringElement)))`);
+
+      assert.strictEqual(sexprs(semanticObj), expected);
+    });
+  });
+});