TypeScript Best Practices in 2025
TypeScript continues to be the go-to choice for building type-safe applications. Here are some best practices to follow.
Use Strict Mode
Always enable strict mode in your tsconfig.json:
{
"compilerOptions": {
"strict": true
}
}{
"compilerOptions": {
"strict": true
}
}Prefer Interfaces for Object Shapes
Use interfaces when defining object shapes:
interface User {
id: string;
name: string;
email: string;
}
function getUser(id: string): User {
// implementation
}interface User {
id: string;
name: string;
email: string;
}
function getUser(id: string): User {
// implementation
}Use Type Guards
Type guards help narrow types safely:
function isString(value: unknown): value is string {
return typeof value === "string";
}
function processValue(value: unknown) {
if (isString(value)) {
console.log(value.toUpperCase());
}
}function isString(value: unknown): value is string {
return typeof value === "string";
}
function processValue(value: unknown) {
if (isString(value)) {
console.log(value.toUpperCase());
}
}Avoid any
Instead of any, use unknown when the type is truly unknown:
// Bad
function parse(input: any): any {
return JSON.parse(input);
}
// Good
function parse(input: string): unknown {
return JSON.parse(input);
}// Bad
function parse(input: any): any {
return JSON.parse(input);
}
// Good
function parse(input: string): unknown {
return JSON.parse(input);
}Conclusion
Following these practices will help you write more maintainable and type-safe TypeScript code.