Unsaved Changes Guard
Stop people navigating away from work they have not saved.
What it adds
A warning on any attempt to leave a form with genuine unsaved changes, covering routing and browser navigation.
What your agent is told to do
5
What your agent is told to do
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1
Compare the current form values against the values it loaded with. Track real changes, not merely whether a field was focused.
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2
Cover all four exits: internal navigation, the back button, a page reload, and closing the tab.
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Name what is at risk in the warning and offer to save rather than only to discard.
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Clear the guard immediately on a successful save, an autosave, or an explicit reset.
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Do not warn on a form the user never meaningfully touched. A guard that fires on an accidental keystroke gets dismissed on reflex, including the time it mattered.
Edge cases it handles
6
Edge cases it handles
6- A field typed into and then changed back is not a change. Compare values, not events.
- A failed save must leave the guard in place and the data intact, not trap the user with no way out.
- A save still in flight should block navigation with a pending state, not a scary dialog.
- The browser's own beforeunload prompt cannot be styled or given custom text. Do not try; use it only for reload and tab close.
- Deliberate sign-out and session expiry must not fight the guard.
- Multi-step forms must guard the whole flow, not each step in isolation.
Definition of done
7
Definition of done
7- Leaving a dirty form warns on internal navigation, back, reload, and tab close.
- An untouched form, or one edited back to its original values, never warns.
- A successful save or reset clears the guard immediately.
- The warning offers to save, not only to discard.
- A failed save leaves the user on the form with their data.
- The feature matches the existing design system.
- No existing functionality is broken.
Related features
Unit Converter
Unit Converter
Let people convert a value between units without leaving the page they are on.
What it does
An inline converter that takes a typed value in one unit and shows the equivalent in another, in place.
How it works
- 1 Start from the units the app actually deals in. A shipping tool needs weight and length; a recipe tool needs volume and temperature. Ship those and leave the rest out.
- 2 Convert as the user types, with the result visible beside the input rather than behind a submit button. Let either side be edited so the conversion runs in both directions.
- 3 Reuse the app's existing number parsing and display formatting rather than writing new ones. If Locale-Aware Numbers and Dates or Number Formatting Component is already present, the converter must render through it so grouping and decimal marks match the rest of the app.
Copy the prompt
No account needed
Add this feature to my app:
https://addthisfeature.com/x/unit-converter
Voice Dictation
Voice Dictation
Put a microphone in text fields so people can speak their input instead of typing it.
What it does
A dictation control on the app's longer text inputs that transcribes speech into the field as the user talks.
How it works
- 1 Add the control to the fields where typing is genuinely tedious: long descriptions, notes, comments, and message bodies. A microphone on a postcode field is clutter.
- 2 Show interim results in the field as they arrive, visually distinct from committed text, so the speaker can see it is working and correct course before they finish.
- 3 Reuse the app's existing Voice Transcription for the server-side path so one recognition configuration and one set of language settings serve both dictation and recorded audio.
Copy the prompt
No account needed
Add this feature to my app:
https://addthisfeature.com/x/voice-dictation
Code Editor Field
Code Editor Field
Edit code, JSON, and config with syntax highlighting instead of a bare textarea.
What it does
A form field backed by a real code editor: syntax highlighting, a language mode per field, and inline validation that tolerates work in progress.
How it works
- 1 Load the editor library lazily, only on views that use it, and render a usable plain textarea until it arrives. It must never block first paint.
- 2 Set the language mode per field from what the field actually holds, and validate against that mode.
- 3 Report syntax errors as you go, but never block typing or reset the content. Half-written JSON is a normal intermediate state; only submission should be gated.
Copy the prompt
No account needed
Add this feature to my app:
https://addthisfeature.com/x/code-editor-field
How it works
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1
Copy the link
Grab the Markdown instruction URL for this feature.
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2
Give it to your AI
Paste it into Claude Code, Cursor, v0, Lovable — whatever you build with.
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3
It inspects, then implements
Your agent reads your existing app first, then adds the feature to fit it.
Works with your stack
These instructions are written to adapt. They tell the agent to detect your framework, match your existing design system, and reuse what you already have — rather than assuming a particular stack.
Need it tighter than that? Customize the feature and tell it exactly what you're running.