Migration From Fractal Required `mandelbrot` Interop

[wesleyboar]

Steps to reproduce the issue

1. Upgrade project from Fractal v1.5 to Fractality v1.6.

2. Notice it may add fs-extra as a dev dependency:
   _{(user error; fixed in TACC/Core-Styles#596)}

   Resolved / Nevermind

   @fractality/mandelbrot imports fs-extra in its runtime code (src/theme.js), but its own published dependencies list does not include fs-extra (only js-beautify and lodash). That means resolution can fail depending on install layout/hoisting rules. Adding fs-extra directly to [the client] repo ("fs-extra": "^11.3.3") makes the dependency explicit and stable for our build/runtime path.

3. Start Fractality.

4. TypeError: mandelbrot is not a function

   Adding default-export interop in fractality.config.js fixed error.

   Details

   @fractality/mandelbrot is ESM and exports a default function. In CommonJS (require(...)), that comes back as a namespace object with a .default property, not a callable function directly. So old-style usage (const mandelbrot = require(...)) throws TypeError: mandelbrot is not a function; the interop line fixes this by using mandelbrotPackage.default || mandelbrotPackage.
   — A.I.

   Commands Run:

   npm view @fractality/mandelbrot dependencies peerDependencies --json
   node -e "const m=require('@fractality/mandelbrot'); ..."
   node -e "const mandelbrot=require('@fractality/mandelbrot'); mandelbrot({}) ..."
   

   Captured Outputs:

   npm view @fractality/mandelbrot dependencies peerDependencies
   --json
   {
     "dependencies": {
       "js-beautify": "^1.15.1",
       "lodash": "^4.17.21"
     },
     "peerDependencies": {
       "@fractality/fractality": ">= 1.5 < 2"
     }
   }
   $ node -e "const m=require(\"@fractality/mandelbrot\"); console
   .log(Object.keys(m)); console.log(typeof m.default); console.lo
   g(typeof m);"
   [ '__esModule', 'default' ]
   function
   object
   $ node -e "const mandelbrot=require(\"@fractality/mandelbrot\")
   ; try { mandelbrot({}); } catch (e) { console.log(e.toString())
   ; }"
   TypeError: mandelbrot is not a function
   

Reproduces how often:

Each time I use wesleyboar/Core-Styles#2 without interop.

Reduced test case

• refactor: migrate from Fractal to Fractality wesleyboar/Core-Styles#2

Context

• Fractality version:

  ├── @fractality/fractality@1.6.3
  ├─┬ @fractality/handlebars@1.4.3
  │ └── @fractality/fractality@1.6.3 deduped
  └─┬ @fractality/mandelbrot@1.12.3
    └── @fractality/fractality@1.6.3 deduped
  

• Node version: v25.4.0

• OS: macOS 15.7.4

[wesleyboar]

I may have mislabeled this. I do not fully understand it. Sorry.