What is TypeScript?

What it is

JavaScript is the language that makes web pages interactive. It is flexible, but it lets you pass the wrong kind of value to the wrong place and only complains once someone is using the page. TypeScript lets developers declare what kind of data each part expects, such as a number, a date, or a customer record.

A checker flags a mismatch as soon as the code is written. The code is then converted into ordinary JavaScript, so it runs anywhere JavaScript does. The checks happen only at build time, so data arriving from outside, such as a form or another system, still has to be validated when the program runs. The tooling comes from Microsoft and is open source.

Why it matters to a business

• Fewer bugs reach users: many errors are caught at the desk instead of in front of a customer.
• Safer changes: when a requirement shifts, the checker points to every place affected.
• Easier handover: the declared types document what the code expects, so a new developer gets up to speed sooner.

How KawaConnect uses TypeScript

We use TypeScript for web application work where the extra checking is worth it, both in the interfaces people click through and in the services behind them. It is part of how we build custom business software that has to keep working as requirements change.

Learn more

• TypeScript on WikipediaA short, neutral description of the language and how it relates to JavaScript, handy for non-developers.
• TypeScript websiteThe official site, including an in-browser playground for trying the language without installing anything.
• TypeScript documentationHandbooks and reference material for developers learning or reviewing TypeScript code.