Native JavaScript access in Flet apps

[7576457]

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• I have searched the opened issues and there are no duplicates

Describe the requested feature

Hi,

I've been working extensively with the charting features in Flet, and while they are a great start, I’ve encountered numerous bugs and limitations. From what I can tell, many of these issues stem from the underlying fl_chart package in Flutter.

Recently, I noticed that the process of importing Flutter packages into Flet has been updated. That inspired me to explore creating my own charting package for Flet. However, while investigating how to approach this, I realized something important: many Flutter chart packages (like the one I intended to use) are originally wrappers around JavaScript libraries — in my case, ECharts.

That made me question the necessity of this three-layer architecture — JavaScript → Flutter → Flet. Since Flet runs on top of Flutter, and Flutter sometimes wraps JS libraries, wouldn’t it be more efficient if Flet could interact with JavaScript directly (at least in web deployments)?

Back in issue #68, the team chose to go with fl_chart, which makes sense at that stage. But after spending a lot of time trying to make it work for more complex use cases, I found that something like ECharts offers far more flexibility and a rich set of features:
👉 https://echarts.apache.org/examples/en/index.html#chart-type-line
Suggestion

Would it be possible to allow running raw JavaScript code directly within Flet, starting with web builds? Even basic JS integration could unlock powerful use cases like advanced charting, animations, or third-party JS libraries — without relying solely on Flutter plugins.

I’m not sure how feasible this is from a technical standpoint, but I’d love to hear your thoughts on it.

Suggest a solution

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Additional details

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[7576457]

Let me share another use case of mine.

I was building an application where I needed to handle an RTSP stream directly in a web app. Unfortunately, I couldn’t find any working solution for RTSP in Flutter when targeting the web. However, in the JavaScript world, there’s a well-established and stable solution for this — WebRTC.

I even created an issue about this here → flet-dev/flet-video#4

How did I solve this for now?

Thankfully, the media_kit library (which we import from Flutter into flet-video) supports streaming formats like HLS and HLSLL. But streams such as MSE or RTSP don’t render properly in the web version — and for me, that’s a critical limitation.