Bolt deployment

TypeScript Compilation Error - Type Mismatch

TypeScript reports type errors that prevent build. Type checking fails even though code appears correct.

Build exits with 'TypeScript error found' message.

Error Messages You Might See

Type 'string | null' is not assignable to type 'string' Property 'name' does not exist on type 'unknown' Argument of type 'string' not assignable to parameter of type 'number' Cannot find name 'SomeType'
Type 'string | null' is not assignable to type 'string'Property 'name' does not exist on type 'unknown'Argument of type 'string' not assignable to parameter of type 'number'Cannot find name 'SomeType'

Common Causes

  1. Variable assigned wrong type
  2. Function argument type mismatch
  3. Null/undefined not handled properly
  4. Object or array structure mismatch
  5. Missing type definitions for library

How to Fix It

Read error message carefully - shows exact line and issue

Use 'as' type assertion sparingly: value as string only when you're sure

Fix null/undefined: use optional chaining (obj?.prop) and nullish coalescing (val ?? default)

For library missing types: npm install @types/library-name

Temporary: add // @ts-ignore above problematic line, then fix later

Real developers can help you.

Daniel Vázquez Daniel Vázquez Software Engineer with over 10 years of experience on Startups, Government, big tech industry & consulting. Taufan Taufan I’m a product-focused engineer and tech leader who builds scalable systems and turns ideas into production-ready platforms. Over the past years, I’ve worked across startups and fast-moving teams, leading backend architecture, improving system reliability, and shipping products used by thousands of users. My strength is not just writing code — but connecting product vision, technical execution, and business impact. Matthew Butler Matthew Butler Systems Development Engineer @ Amazon Web Services zipking zipking I am a technologist and product builder dedicated to creating high-impact solutions at the intersection of AI and specialized markets. Currently, I am focused on PropScan (EstateGuard), an AI-driven SaaS platform tailored for the Japanese real estate industry, and exploring the potential of Archify. As an INFJ-T, I approach development with a "systems-thinking" mindset—balancing technical precision with a deep understanding of user needs. I particularly enjoy the challenge of architecting Vertical AI SaaS and optimizing Small Language Models (SLMs) to solve specific, real-world business problems. Whether I'm in a CTO-level leadership role or hands-on with the code, I thrive on building tools that turn complex data into actionable value. Nam Tran Nam Tran 10 years as fullstack developer Richard McSorley Richard McSorley Full-Stack Software Engineer with 8+ years building high-performance applications for enterprise clients. Shipped production systems at Walmart (4,000+ stores), Cigna (20M+ users), and Arkansas Blue Cross. 5 patents in retail/supply chain tech. Currently focused on AI integrations, automation tools, and TypeScript-first architectures. Franck Plazanet Franck Plazanet I am a Strategic Engineering Leader with over 8 years of experience building high-availability enterprise systems and scaling high-performing technical teams. My focus is on bridging the gap between complex technology and business growth. Core Expertise: 🚀 Leadership: Managing and coaching teams of 15+ engineers, fostering a culture of accountability and continuous improvement. 🏗️ Architecture: Enterprise Core Systems, Multi-system Integration (ERP/API/ETL), and Core Database Structure. ☁️ Cloud & Scale: AWS Expert; architected systems handling 10B+ monthly requests and managing 100k+ SKUs. 📈 Business Impact: Aligning tech strategy with P&L goals to drive $70k+ in monthly recurring revenue. I thrive on "out-of-the-box" thinking to solve complex technical bottlenecks and am always looking for ways to use automation to improve business productivity. Stanislav Prigodich Stanislav Prigodich 15+ years building iOS and web apps at startups and enterprise companies. I want to use that experience to help builders ship real products - when something breaks, I'm here to fix it. Victor Denisov Victor Denisov Developer Tejas Chokhawala Tejas Chokhawala Full-stack engineer with 5 years experience building production web apps using React, Next.js and TypeScript. Focused on performance, clean architecture and shipping fast. Experienced with Supabase/Postgres backends, Stripe billing, and building AI-assisted developer tools.

You don't need to be technical. Just describe what's wrong and a verified developer will handle the rest.

Get Help

Frequently Asked Questions

What's the difference between unknown and any?

unknown is safe - requires type checking. any bypasses checking entirely. Always prefer unknown

How do I handle null/undefined?

Use optional chaining: obj?.prop?. Use nullish coalescing: val ?? default

Should I use 'as' type assertion?

Rarely. It bypasses type checking. Use when you're 100% sure of the type

Related Bolt Issues

Can't fix it yourself?
Real developers can help.

You don't need to be technical. Just describe what's wrong and a verified developer will handle the rest.

Get Help