Type Rule Options

Use these options when you want conditionals to express exactly how your app treats zero, empty strings, and absent objects. type/strict-boolean-expressions is opt-in and requires type-aware linting; setting its options alone does not enable it.

Start with the configuration and Bad/Good examples below, then run vp run lint and review the reported conditions. The Rule Options guide explains severity, scoped replacement, and how to configure rules with Vite+ or the standalone CLI.

type/strict-boolean-expressions

Enable the native type-aware rule explicitly under linter.rules. It belongs to no preset. Use linter.ruleOptions to choose which non-boolean conditions to allow. The native checker projection already uses strict checking.

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

export default defineConfig({
  lint: {
    vize: {
      typeAware: true,
      rules: {
        "type/strict-boolean-expressions": "error",
      },
      ruleOptions: {
        "type/strict-boolean-expressions": {
          allowString: false,
          allowNumber: false,
          allowNullableObject: false,
        },
      },
    },
  },
});

With these options, the following script and template conditions are Bad:

<script setup lang="ts">
defineProps<{ count: number; title: string; element?: HTMLElement }>();
</script>
<template>
  <p v-if="count">Items</p>
  <p v-show="title">Title</p>
  <p v-if="element">Element</p>
</template>

Good: use comparisons that state the intended treatment of zero, empty text and absent objects.

<template>
  <p v-if="count > 0">Items</p>
  <p v-show="title !== ''">Title</p>
  <p v-if="element != null">Element</p>
</template>

Defaults: allowString, allowNumber, and allowNullableObject are true. allowNullableBoolean, allowNullableString, allowNullableNumber, allowNullableEnum, and allowAny are false. Each field takes a boolean. Options alone do not enable the rule; later matching entries replace the whole option object and explicit off still wins. Assertion functions, array predicates and external/Pug templates are outside this rule's scope.