architecture/prop-count · Prop count

Components taking many props are doing too much.

Severity: info · Category: architecture

What it checks

Flags a component that destructures more than 6 props from $props(). A rest element (...rest) beside named props doesn’t stop the named props from being counted. Only a bare rest element with no named props, or a non-destructured $props(), is not counted.

The threshold is measured, not guessed. 6 is the median per-repository 90th percentile of prop counts across a survey of real Svelte 5 codebases, so in a typical project, a component with 7 or more props is wider than roughly nine in ten of the components whose props can be counted. Widening the survey to 13 repositories left the number unchanged, and counting named props destructured beside a ...rest element moves the per-repo p90 median only to 6.5, close enough that the default remains 6.

Why it matters

A component taking many props is usually doing too much; grouping related props or splitting the component keeps its API understandable.

How to fix

<script>
  // Group related props into an object instead of many flat props.
  let { user, layout } = $props(); // user: { name, avatar, … }
</script>

Configuration

Option	Type	Default
`max`	integer	6

export default {
  rules: { 'architecture/prop-count': { options: { max: 10 } } }
};

Mode differences

None. This rule reads source, the same .svelte and .ts files, everywhere it runs. The CLI, the Vite plugin’s build pass, and the live dashboard’s static baseline all report it identically, and the rendered-HTML pass never re-evaluates it. Scoping a run with --route skips it: component-scoped rules have no route to attribute a finding to.

Disabling

Silence a single occurrence with  on the line above it, or turn the rule off:

export default {
  rules: {
    'architecture/prop-count': 'off'
  }
};