Adds helper

package.json

@@ -33,7 +33,7 @@
   "devDependencies": {
     "@types/chai": "^4.3.4",
     "@types/lodash": "^4.14.199",
-    "@types/mocha": "^10.0.1",
+    "@types/mocha": "^10.0.2",
     "@types/pluralize": "^0.0.31",
     "@typescript-eslint/eslint-plugin": "^5.12.1",
     "@typescript-eslint/parser": "^5.12.1",

src/getVariablesFromHandlebarsTemplate.ts

@@ -0,0 +1,116 @@
+import handlebars from 'handlebars';
+
+/**
+ * Parse AST for variables
+ *
+ * @param statement - Statement to parse
+ * @returns Variables
+ */
+function parseHandlebarsAst(statement: hbs.AST.Statement): {
+  [k in string]: unknown;
+} {
+  // No variables
+  if (statement.type === 'ContentStatement') {
+    return {};
+  }
+
+  if (statement.type === 'PartialStatement') {
+    const moustacheStatement = statement as hbs.AST.PartialStatement;
+    const pathStatement = moustacheStatement.name as hbs.AST.PathExpression;
+    return {
+      [pathStatement.original]: 'partial',
+    };
+  }
+
+  // Parse variables from {{ var }}
+  if (statement.type === 'MustacheStatement') {
+    const moustacheStatement = statement as hbs.AST.MustacheStatement;
+    const paramsExpressionList =
+      moustacheStatement.params as hbs.AST.PathExpression[];
+    const pathExpression = moustacheStatement.path as hbs.AST.PathExpression;
+    const vars = [
+      ...paramsExpressionList.map(({ original }) => original),
+      pathExpression.original,
+    ].filter((x) => !!x);
+    return vars.reduce((acc, x) => Object.assign(acc, { [x]: null }), {});
+  }
+
+  // Parse from {{#each}} or {{#with}}
+  if (statement.type === 'BlockStatement' && statement) {
+    const moustacheStatement = statement as hbs.AST.MustacheStatement;
+    const paramsExpressionList =
+      moustacheStatement.params as hbs.AST.PathExpression[];
+    // eslint-disable-next-line @typescript-eslint/no-explicit-any
+    const program = (moustacheStatement as any).program as hbs.AST.Program;
+    const param = paramsExpressionList[0] as unknown as
+      | hbs.AST.PathExpression
+      | hbs.AST.SubExpression;
+    const pathExpression = moustacheStatement.path as hbs.AST.PathExpression;
+    if (param.type === 'SubExpression') {
+      return program.body
+        .map(parseHandlebarsAst)
+        .reduce((acc, obj) => Object.assign(acc, obj), {});
+    }
+
+    if (pathExpression.original === 'each') {
+      return {
+        [param.original]: [
+          program.body
+            .map(parseHandlebarsAst)
+            .reduce((acc, obj) => Object.assign(acc, obj), {}),
+        ],
+      };
+    }
+
+    return {
+      [param.original]: program.body
+        .map(parseHandlebarsAst)
+        .reduce((acc, obj) => Object.assign(acc, obj), {}),
+    };
+  }
+  throw new Error(`Unknown statement: ${statement.type}`);
+}
+
+/**
+ * Get variables from handlebars template
+ *
+ * @param template - Template
+ * @returns Variables
+ */
+export function getVariablesFromHandlebarsTemplate(template: string): {
+  [k in string]: unknown;
+} {
+  const ast = handlebars.parseWithoutProcessing(template);
+
+  const results = ast.body.map(parseHandlebarsAst);
+  return results.reduce((acc, data) => {
+    Object.entries(data).forEach(([k, v]) => {
+      const existing = acc[k];
+      if (!existing) {
+        return Object.assign(acc, { [k]: v });
+      }
+      if (Array.isArray(existing) && Array.isArray(v)) {
+        return Object.assign(acc, {
+          [k]: [
+            {
+              ...existing[0],
+              ...v[0],
+            },
+          ],
+        });
+      }
+      if (typeof existing === 'object' && typeof v === 'object') {
+        return Object.assign(acc, {
+          [k]: {
+            ...existing,
+            ...v,
+          },
+        });
+      }
+      return Object.assign(acc, {
+        [k]: v,
+      });
+    });
+    return acc;
+  }, {});
+}

src/index.ts

@@ -1,2 +1,3 @@
 export * from './change-case';
 export * from './createHandlebars';
+export * from './getVariablesFromHandlebarsTemplate';

src/tests/getVariablesFromHandlebarsTemplate.test.ts

@@ -0,0 +1,61 @@
+import { expect } from 'chai';
+
+import { getVariablesFromHandlebarsTemplate } from '../index';
+
+const TEST_HBS = `
+<p>
+  You are an experienced project manager, constantly juggling a variety of different tasks.
+  Other employees at your company are very busy.
+  They quickly record notes in slack of things that they want to look into later.
+  You are tasked with reviewing those raw notes, and turning them into a structured
+  form that will make the notes more easily indexable by the employee when they have more time to review the information.
+  {{{ description }}}. Return a JSON object in the following format:
+
+  ({{#each parameters}}{{ name }} - {{slug}}, {{/each}}clarification).
+</p>
+
+{{> promptPartialTodaysDate }}
+
+{{> promptPartialTranscendProducts }}
+
+
+{{#with dog}}{{cat}} - {{fish}}{{/with}}
+
+{{#if (listLen extraContext)}}
+{{#each extraContext}}
+{{ name }}
+{{/each}}
+{{/if}}
+
+<p>
+  The following rules define each of the input parameters:
+  <ul>
+  {{#each parameters}}
+    <li>{{ name }}: {{{ description }}}</li>
+  {{/each}}
+  </ul>
+</p>
+
+{{#with dog}} {{meow}}{{/with}}
+
+<p>
+  If any of the parameters are not known, it should be set to null.
+  If anything is not clear, return a prompt in the clarification key of the response asking for further detail
+</p>`;
+
+describe('getVariablesFromHandlebars', () => {
+  it('should merge together', () => {
+    expect(getVariablesFromHandlebarsTemplate(TEST_HBS)).to.deep.equal({
+      description: null,
+      parameters: [{ name: null, slug: null, description: null }],
+      dog: { cat: null, fish: null, meow: null },
+      extraContext: [
+        {
+          name: null,
+        },
+      ],
+      promptPartialTodaysDate: 'partial',
+      promptPartialTranscendProducts: 'partial',
+    });
+  });
+});

yarn.lock

@@ -309,7 +309,7 @@ __metadata:
     "@transcend-io/type-utils": ^1.1.1
     "@types/chai": ^4.3.4
     "@types/lodash": ^4.14.199
-    "@types/mocha": ^10.0.1
+    "@types/mocha": ^10.0.2
     "@types/pluralize": ^0.0.31
     "@typescript-eslint/eslint-plugin": ^5.12.1
     "@typescript-eslint/parser": ^5.12.1
@@ -441,7 +441,7 @@ __metadata:
   languageName: node
   linkType: hard
 
-"@types/mocha@npm:^10.0.1":
+"@types/mocha@npm:^10.0.2":
   version: 10.0.2
   resolution: "@types/mocha@npm:10.0.2"
   checksum: a78a02691f102beb02f9ec435458107d21b518fc477c3b2f37c90b8e70b67bff888351715ae173bd31ede25ee5e0d688aefb0faf4284034d08ba63027c8b0c01