vize:croquis/cf/watcheffect-async

watchEffect starts an async task and cannot clean up the previous run.

Default severity: error
Applies to: Analyzed component graph and the supported facts described below
Automatic fix: None; review related files and apply the repair
Options: No per-code options; supported CLI findings accept severity overrides

import { defineConfig } from "@vizejs/vite-plugin/vite-plus";

export default defineConfig({
  lint: {
    vize: { preset: "incremental", crossFile: true,
      rules: { "croquis/cf/watcheffect-async": "warn" },
    },
  },
});

vp run lint

Shared project files

Use these unchanged files in both Bad and Good. Install the imported packages in the project: Vue, plus vue-router or Pinia where shown. Follow any version-specific support note. The entry root makes the component relationship explicit.

main.ts

import { createApp } from "vue";
import Root from "./SearchPage.vue";
createApp(Root).mount("#app");

index.html

<div id="app"></div>
<script type="module" src="/main.ts"></script>

api.ts

export interface Result { items: string[]; }
export async function load(query: string, options?: { signal?: AbortSignal }): Promise<Result> {
  const response = await fetch(`/search?q=${encodeURIComponent(query)}`, options);
  return response.json();
}

Bad

The async watchEffect mixes implicit dependency collection with an awaited request and no invalidation guard.

SearchPage.vue

<script setup lang="ts">
import { ref } from "vue";
import SearchResults from "./SearchResults.vue";

const query = ref("");
</script>

<template>
  <SearchResults :query="query" />
</template>

SearchResults.vue

<script setup lang="ts">
import { load, type Result } from "./api";
import { ref, watchEffect } from "vue";

const props = defineProps<{ query: string }>();
const result = ref<Result | null>(null);

watchEffect(async () => {
  result.value = await load(props.query);
});
</script>

Good

An explicit watch(() => props.query, ...) declares the source, registers request cleanup, and refuses a stale response after invalidation.

SearchPage.vue

<script setup lang="ts">
import { ref } from "vue";
import SearchResults from "./SearchResults.vue";

const query = ref("");
</script>

<template>
  <SearchResults :query="query" />
</template>

SearchResults.vue

<script setup lang="ts">
import { load, type Result } from "./api";
import { ref, watch } from "vue";

const props = defineProps<{ query: string }>();
const result = ref<Result | null>(null);

watch(
  () => props.query,
  async (value, _oldValue, onCleanup) => {
    const controller = new AbortController();
    let active = true;

    onCleanup(() => {
      active = false;
      controller.abort();
    });

    const next = await load(value, { signal: controller.signal });
    if (active) result.value = next;
  },
);
</script>

The Good files demonstrate the change described above; other diagnostics can still apply to the complete project.

Public explanation

Producer

Cross-file index