@flareapp/sveltekit

SvelteKit integration for Flare error tracking and logging. Wraps SvelteKit's client and server handleError hooks to report unexpected errors with route context. Also provides manual capture helpers and route tracking for browser-side reports.

Installation

npm install @flareapp/sveltekit @flareapp/js

Quick start

Set up Flare in your SvelteKit hooks:

// src/hooks.client.ts
import { dev } from '$app/environment';
import { flare } from '@flareapp/js';
import { handleErrorWithFlare } from '@flareapp/sveltekit/client';

if (!dev) {
    flare.light('YOUR_FLARE_API_KEY');
}

export const handleError = handleErrorWithFlare();

// src/hooks.server.ts
import { dev } from '$app/environment';
import { flare } from '@flareapp/js';
import { handleErrorWithFlare } from '@flareapp/sveltekit/server';

if (!dev) {
    flare.light('YOUR_FLARE_API_KEY');
}

export const handleError = handleErrorWithFlare();

Logging

Beyond errors, the client can send structured logs. Logs are opt-in: enable them with enableLogs, then call any of the eight syslog levels (debug, info, notice, warning, error, critical, alert, emergency).

import { flare } from '@flareapp/js';

flare.configure({ enableLogs: true });

flare.logger.info('Checkout started', { cartId: cart.id, total: cart.total });

Identifying users

import { flare } from '@flareapp/js';

flare.setUser({ id: 123, email: '[email protected]', fullName: 'Jane Doe' });

See the JavaScript identifying-users docs for the full field list. Pass null to clear.

Hover-preloaded fetches in traces

SvelteKit's recommended default, data-sveltekit-preload-data="hover", starts a route's load function, including its fetch, as soon as a visitor hovers a link — before they click it. If they never click, a trace for the page they were on can still show a fetch for the route they hovered but never opened. That is a correct record of what the browser did, not a bug, but it can read as wrong data in a waterfall. Setting data-sveltekit-preload-data to a less eager value (for example "tap") avoids it.

Documentation

Full documentation on handleErrorWithFlare, captureError, trackRouteContext, lifecycle callbacks, and more is available at flareapp.io/docs/svelte/general/installation.

Compatibility

• Svelte 5.3+
• SvelteKit 2.12+

License

The MIT License (MIT). Please see License File for more information.