vitest-dev/vitest · error · Error

Tag name " " is invalid. Tag names cannot be a logical…

Error message

Tag name "${tag.name}" is invalid. Tag names cannot be a logical operator like "and", "or", "not".

What it means

Tag names cannot be the reserved logical operators `and`, `or`, `not` (case-insensitive, whitespace-trimmed). These words are keywords in Vitest's tag filter expression grammar, so using one as a tag name would collide with operator tokenisation.

Solutions

Pick a non-reserved name: `logical-and`, `or-check`, `negated`.
Namespace the tag: `myteam.and`.
Validate names against the reserved list before exporting config.

Example fix

// before
export default defineConfig({ test: { tags: [{ name: 'or' }] } })

// after
export default defineConfig({ test: { tags: [{ name: 'or-gate' }] } })

Defensive patterns

Strategy: validation

Validate before calling

const RESERVED_WORDS = /^\s*(?:and|or|not)\s*$/i
function assertNotReservedWord(name: string): void {
  if (RESERVED_WORDS.test(name)) {
    throw new Error(`Tag name "${name}" is a reserved logical operator`)
  }
}

rawTags.forEach(t => assertNotReservedWord(t.name))

Type guard

function isNonReservedName(name: string): boolean {
  return typeof name === 'string' && !/^\s*(?:and|or|not)\s*$/i.test(name)
}

Prevention

Namespace tag names to avoid accidental collisions with operators.
Maintain a denylist of reserved words when generating tags programmatically.
Prefer domain-specific names over generic logical terms.

When it happens

Trigger: `{ name: 'and' }`, `{ name: 'OR' }`, `{ name: ' not ' }`, or any case variant matching `^\s*(?:and|or|not)\s*$`.

Common situations: Naming tags after domain concepts that happen to be these words; auto-generating tags from a taxonomy that includes operator-like terms.

Related errors

AI-assisted analysis of vitest-dev/vitest@1fa9837ec2 (2026-08-11). Data as JSON: /api/errors/a92daa33e369dfac. Report an issue: GitHub.

Appendix: source

Thrown at packages/vitest/src/node/config/resolveConfig.ts:302

  // shallow copy tags array to avoid mutating user config
  resolved.tags = [...resolved.tags || []]
  const definedTags = new Set<string>()
  resolved.tags.forEach((tag) => {
    if (!tag.name || typeof tag.name !== 'string') {
      throw new Error(`Each tag defined in "test.tags" must have a "name" property, received: ${JSON.stringify(tag)}`)
    }
    if (definedTags.has(tag.name)) {
      throw new Error(`Tag name "${tag.name}" is already defined in "test.tags". Tag names must be unique.`)
    }
    if (/\s/.test(tag.name)) {
      throw new Error(`Tag name "${tag.name}" is invalid. Tag names cannot contain spaces.`)
    }
    if (/[!()*|&]/.test(tag.name)) {
      throw new Error(`Tag name "${tag.name}" is invalid. Tag names cannot contain "!", "*", "&", "|", "(", or ")".`)
    }
    if (/^\s*(?:and|or|not)\s*$/i.test(tag.name)) {
      throw new Error(`Tag name "${tag.name}" is invalid. Tag names cannot be a logical operator like "and", "or", "not".`)
    }
    if (typeof tag.retry === 'object' && typeof tag.retry.condition === 'function') {
      throw new TypeError(`Tag "${tag.name}": retry.condition function cannot be used inside a config file. Use a RegExp pattern instead, or define the function in your test file.`)
    }
    if (tag.priority != null && (typeof tag.priority !== 'number' || tag.priority < 0)) {
      throw new TypeError(`Tag "${tag.name}": priority must be a non-negative number.`)
    }
    definedTags.add(tag.name)
  })

  resolved.name = typeof options.name === 'string'
    ? options.name
    : (options.name?.label || '')

  resolved.color = typeof options.name !== 'string' ? options.name?.color : undefined

  if (resolved.environment === 'browser') {
    throw new Error(`Looks like you set "test.environment" to "browser". To enable Browser Mode, use "test.browser.enabled" instead.`)

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