PERF009 · Heavy dependency import

Severity: info · Category: performance

What it checks

Flags an import from a well-known heavy / non-tree-shakeable package (currently lodash, moment). Matched by exact specifier, so a subpath import like lodash/debounce is not flagged. Static (CLI) analysis of src/**/*.svelte scripts.

Why it matters

Importing a large, non-tree-shakeable package pulls its whole weight into the bundle even when you use a fraction of it, slowing page load.

How to fix

<script>
  // Instead of:  import _ from 'lodash';
  import debounce from 'lodash/debounce'; // or use lodash-es

  // Instead of:  import moment from 'moment';
  import { format } from 'date-fns'; // or dayjs
</script>