Implementation:Cypress io Cypress Type Check and Lint

Knowledge Sources	Cypress
Domains	Development, Quality_Assurance
Last Updated	2026-02-12 00:00 GMT

Overview

Concrete tools for cross-package TypeScript type checking and ESLint linting provided by custom scripts and shared configuration.

Description

Two main tools handle code quality:

• scripts/type_check.js (L1-83): Uses commander for CLI parsing and listr2 for concurrent type checking across packages. Runs tsc --noEmit for each specified package.
• .eslintrc.js (L1-112): Root ESLint config extending @cypress/eslint-config with project-specific rules.
• packages/ts/tsconfig.json (L1-118): Base TypeScript configuration with target: ES2018, strict: true, skipLibCheck: true.

Usage

Run type checking and linting before committing changes or as part of CI validation.

Code Reference

Source Location

• Repository: cypress-io/cypress
• Files:
  • scripts/type_check.js:L1-83 (type check runner)
  • .eslintrc.js:L1-112 (ESLint config)
  • packages/ts/tsconfig.json:L1-118 (base TypeScript config)

Signature

# Type checking
node scripts/type_check.js -p packages/config packages/server packages/driver

# Linting
eslint --fix "packages/*/src/**/*.{ts,tsx}"

Import

# From repo root
node scripts/type_check.js -p <packages...>
npx eslint --fix .

I/O Contract

Inputs

Name	Type	Required	Description
-p packages	string[]	Yes (type_check)	Package paths to type check
Source files	.ts/.tsx	Yes	TypeScript source files
.eslintrc.js	config	Yes	ESLint configuration
tsconfig.json	config	Yes	TypeScript configuration

Outputs

Name	Type	Description
Type errors	stderr	TypeScript type errors with file:line references
Lint errors	stderr	ESLint violations and warnings
Exit code	number	0=clean, 1=errors found

Usage Examples

Local Development

# Check types for specific packages
node scripts/type_check.js -p packages/config packages/server

# Lint and auto-fix
npx eslint --fix "packages/config/src/**/*.ts"

# CI validation (both)
yarn lint && node scripts/type_check.js -p packages/*

Related Pages

Implements Principle

• Principle:Cypress_io_Cypress_Code_Quality_Verification