Implementation:Webdriverio Webdriverio ESLint AwaitExpect

Knowledge Sources	Webdriverio_Webdriverio
Domains	Linting, Test_Quality
Last Updated	2026-02-12 00:00 GMT

Overview

ESLint rule that enforces the use of await before WebdriverIO expect statements to prevent unhandled asynchronous assertions.

Description

The await-expect rule is defined as a Rule.RuleModule and categorized as a "problem" type ESLint rule. It inspects CallExpression AST nodes to determine whether an expect call is chained with a recognized WebdriverIO matcher (such as toBeDisplayed, toHaveText, toExist, etc. from the MATCHERS constant). If the expect-matcher call appears as a bare ExpressionStatement (i.e., without an await prefix), the rule reports a missingAwait error. This ensures that all WebdriverIO assertion promises are properly awaited, preventing silent test passes.

Usage

Use this rule in any WebdriverIO test project by enabling it in your ESLint configuration. It is particularly important in projects using WebdriverIO's asynchronous expect API where forgetting await would cause assertions to be silently skipped, leading to false-positive test results.

Code Reference

Source Location

• Repository: Webdriverio_Webdriverio
• File: packages/eslint-plugin-wdio/src/rules/await-expect.ts

Signature

const rule: Rule.RuleModule = {
    meta: {
        type: 'problem',
        docs: {
            description: 'expect must be prefixed with await',
            category: 'Possible Errors',
            recommended: false,
        },
        messages: {
            missingAwait: 'Missing await before an expect statement'
        },
        hasSuggestions: true
    },
    create: function (context: Rule.RuleContext): Rule.RuleListener
}

export default rule

Import

import rule from '@wdio/eslint-plugin-wdio/src/rules/await-expect'

I/O Contract

Inputs

Name	Type	Required	Description
context	Rule.RuleContext	Yes	ESLint rule context providing the AST and reporting API
node	CallExpression	Yes	AST node representing a function call expression to be validated

Outputs

Name	Type	Description
Rule.RuleListener	object	Listener object with a CallExpression visitor that reports missingAwait when an expect-matcher chain lacks await

Usage Examples

// .eslintrc.js configuration
module.exports = {
    plugins: ['wdio'],
    rules: {
        'wdio/await-expect': 'error'
    }
}

// Incorrect - will trigger the rule
expect(el).toBeDisplayed()

// Correct - properly awaited
await expect(el).toBeDisplayed()
await expect(browser).toHaveUrl('https://example.com')

Related Pages

• Principle:Webdriverio_Webdriverio_ESLint_Plugin_Architecture