Exploring the Contrast: Helpers and Utils Demystified
Tags: programming, architecture, tutorial, productivity
Published: 2023-10-11 14:24:39

**Helpers** and **utils** are both commonly used terms in software development to refer to classes or modules that provide common functionality. However, there is a subtle difference between the two.

**Helpers** are typically specific to a particular project or layer of an application. They provide functionality that is needed by other classes or modules in the same project, but is not general-purpose enough to be reused in other projects. For example, a helper class might provide methods for mapping between database entities and DTOs, or for validating user input.

**Utils**, on the other hand, are general-purpose classes or modules that can be reused in multiple projects. They provide functionality that is common to many different types of applications, such as string manipulation, date and time formatting, or mathematical operations. For example, a utils module might provide functions for converting strings to different encodings, parsing dates and times, or calculating the square root of a number.

| Characteristic | Helper | Util |
| ----------- | ----------- | ----------- |
| Scope | Project- or layer-specific | General-purpose |
| Reusability | Not typically reused in other projects | Can be reused in multiple projects |
| Examples | Mapping database entities to DTOs, validating user input | String manipulation, date and time formatting, mathematical operations |

In general, it is best to use utils whenever possible, as this can help to reduce code duplication and make your code more reusable. However, there are some cases where it is necessary to create a helper class, such as when you need to provide functionality that is specific to your project or layer of an application.

Example code for helpers and utils in TypeScript:

**Helper:**
```ts
export function validatePassword(password: string): boolean {
  if (password.length < 8) {
    throw new Error("Password must be at least 8 characters long");
  }
  if (!/[A-Za-z]/.test(password) || !/[0-9]/.test(password)) {
    throw new Error("Password must contain at least one letter and one number");
  }
  return true;
}
```
This helper class provides a method for validating user passwords. It can be used in other classes or modules in the same project to ensure that all user passwords are strong and secure.

**Util:**

```ts
import { format } from "date-fns";

export function formatDateTime(datetimeObj: Date, formatStr = "yyyy-MM-dd HH:mm:ss"): string {
  return format(datetimeObj, formatStr);
}
```

This util function formats a date time object into a string using the `date-fns` library. It can be used in any class or module in the project to format date time objects consistently.

**Tips for writing good helpers and utils**
Here are some tips for writing good helpers and utils:

- **Make them clear and concise.** The code in your helpers and utils should be easy to read and understand. Avoid using complex logic or unnecessary abstractions.
- **Document them well.** Include clear and concise documentation for all of the methods and functions in your helpers and utils. This will help other developers to understand how to use them.
- **Test them thoroughly.** Make sure to write unit tests for all of the methods and functions in your helpers and utils. This will help to ensure that they work correctly.
- **Keep them up to date.** As your project evolves, make sure to update your helpers and utils as needed. This will help to ensure that they continue to work correctly and meet the needs of your project.