TypeScript Best Practices for 2025

TypeScript continues to evolve, and with it, our best practices. Here's what you need to know for 2024.

Type Safety First

Always aim for maximum type safety in your applications:

// Bad
function process(data: any) {
  return data.value;
}

// Good
interface ProcessData {
  value: string;
}

function process(data: ProcessData) {
  return data.value;
}

Use Modern TypeScript Features

1. Template Literal Types

type IconSize = "sm" | "md" | "lg";
type IconVariant = "solid" | "outline";
type IconName = `icon-${IconSize}-${IconVariant}`;

2. Satisfies Operator

const theme = {
  colors: {
    primary: "#0099ff",
    secondary: "#ff0099",
  },
  spacing: {
    sm: "0.5rem",
    md: "1rem",
  },
} satisfies Record<string, Record<string, string>>;

Type Inference

Let TypeScript infer types when possible:

// Bad
const numbers: number[] = [1, 2, 3];

// Good
const numbers = [1, 2, 3];

Error Handling

Use discriminated unions for better error handling:

type Result<T> = { success: true; data: T } | { success: false; error: Error };

function processData<T>(result: Result<T>) {
  if (result.success) {
    return result.data;
  } else {
    console.error(result.error);
  }
}

Conclusion

Following these practices will help you write more maintainable and safer TypeScript code.