MCVE for https://github.com/11ty/eleventy/issues/664

about.md

title	tags
about	post

My About Page

index.md

title	tags
index	post

My Home Page

package.json

{
  "name": "1ttyData",
  "version": "1.0.0",
  "description": "",
  "author": "",
  "license": "ISC",
  "devDependencies": {
    "@11ty/eleventy": "^0.9.0-beta.3"
  }
}

search-index.11ty.js

class SearchIndex {
    data() {
      return {
          // https://www.11ty.io/docs/languages/javascript/#permalinks
        permalink: "/search2.json",
      };
    }
  
    render(data) {
        let search = data.collections.post.map(item => {
          return {
            url: item.url,
            title: item.data.title,
            text: item.data.templateContent
          }  
        })
        var stringify = JSON.stringify(search, null, 2)
        return stringify;
      }
  }
  
  module.exports = SearchIndex;

search-index.njk

---
permalink: search.json
---
[
{%- for item in collections.post -%}
  {
    "url" : "{{ item.url }}",
    "title" : "{{ item.data.title }}",
    "text" : "{{ item.templateContent }}"
  }{% if not loop.last %},{% else %}{%- endif -%}
{%- endfor -%}
]