JS to TypeScript-JS to TypeScript Conversion

Example

JavaScript: function add(a, b) { return a + b; } TypeScript: function add(a: number, b: number): number { return a + b; }

Scenario

In a typical web development project, ensuring that function parameters and return types are explicitly declared to prevent type-related bugs during compilation rather than at runtime.

Example

JavaScript using jQuery: $('div').hide(); TypeScript with native DOM: document.querySelectorAll('div').forEach(div => div.style.display = 'none');

Scenario

When modernizing an existing web application to improve performance and compatibility across modern browsers without relying on third-party libraries like jQuery.

Example

JavaScript: function processUser(user) { return user.name; } TypeScript: function processUser(user: { name: string } | null): string | null { return user ? user.name : null; }

Scenario

In enterprise-level applications where null values can lead to application failures, adding strict null checks can significantly prevent common errors related to undefined or null values.

Example

JavaScript: var x = function(y) { return y * y; } TypeScript: const x = (y: number): number => y * y;

Scenario

Refactoring an older codebase to use modern ES6+ syntax and features, improving code readability and reducing potential scope issues with var declarations.