Книги
TypeScript
Розділ 9. Тестування та відлагодження
Виведення налагоджувальної інформації

TypeScript:
Виведення налагоджувальної інформації

How to: (Як це зробити:) 

// Simple console log
console.log('Hello, debugging world!');

// Printing a variable
let lifeMeaning: number = 42;
console.log(`The meaning of life is ${lifeMeaning}`);

// Sample output:
// Hello, debugging world!
// The meaning of life is 42

// Grouping logs
console.group('User Details');
console.log('Name: John Doe');
console.log('Age: 42');
console.groupEnd();

// Sample output:
// User Details
// Name: John Doe
// Age: 42

Deep Dive (Поглиблений Розбір)

Historically, print statements were a primary way to troubleshoot code. In TypeScript, console.log is the go-to. It’s simple but powerful. You’ve also got console.warn for warnings and console.error for errors, which helps differentiate messages. Not just primitive values, you can print objects and they’ll be nicely formatted. Fancy features like console.table can display arrays and objects in a tabular format.

Alternatives? You could throw exceptions or use debugging tools that step through code, like the debugger in Visual Studio Code, but they are more complex. As for implementation, TypeScript’s console calls are part of the ambient global scope, so no imports are necessary. These debug statements are usually stripped out in production builds, making the performance impact negligible in live environments.

See Also (Дивіться також)

Використання інтерактивної оболонки (REPL)