MakeSafe

Acknowledgements

• This wonderful tweet
• Typescript library boilerplate

Installation

This library is published in the NPM registry and can be installed using any compatible package manager.

npm install makesafe --save

# For Yarn, use the command below.
yarn add makesafe

Installation from CDN

This module has an UMD bundle available through JSDelivr and Unpkg CDNs.

<!-- For UNPKG use the code below. -->
<script src="https://unpkg.com/makesafe"></script>

<!-- For JSDelivr use the code below. -->
<script src="https://cdn.jsdelivr.net/npm/makesafe"></script>

<script>
  // UMD module is exposed through the "makeSafe" global variable.
  console.log(makeSafe);
</script>

Description

What does this package do?

This is a TypeScript packag that defines a Result type and a makeSafe function that takes a function as its argument and returns a new function that wraps the original function with error-handling logic. The wrapped function returns a Result object that contains either the result of the original function or an error object if the original function throws an error.

What is the Result type?

The Result type is a union type that represents either a successful result or a failure result. It has two properties: ok, which is a boolean that indicates whether the result is successful or not, and either a value property or an error property, depending on whether the result is successful or not.

If ok is true, then the value property will contain the successful result of the function call. If ok is false, then the error property will contain an unknown error object that was thrown by the original function.

What is the makeSafe function?

The makeSafe function takes a function as its argument and returns a new function that wraps the original function with error-handling logic. The wrapped function returns a Result object that contains either the result of the original function or an error object if the original function throws an error.

The makeSafe function is a higher-order function that returns a new function. The returned function has the same argument types as the original function, and its return type is a Result object that wraps the return type of the original function.

How to use the makeSafe function?

To use the makeSafe function, you need to pass a function to it as an argument. The function should take some arguments and return some value.

Once you have the wrapped function, you can call it like a normal function, passing the same arguments that you would pass to the original function. The wrapped function will return a Result object that contains either the result of the original function or an error object if the original function throws an error.

You can check whether the result is successful or not by checking the value of the ok property. If ok is true, then the value property will contain the successful result of the function call. If ok is false, then the error property will contain an unknown error object that was thrown by the original function.

Example usage

const randomlyFail = makeSafe((input: number) => {
  if (input > 0.5) {
    throw new Error('oops');
  }
  return {
    input,
  };
});

const result = randomlyFail(Math.random());
// result is of type Result<{ input: number }>
if (result.ok) {
  console.log(result.value);
} else {
  console.error(result.error);
}

In this example, we create a new function randomlyFail by passing an anonymous function to the makeSafe function. The anonymous function takes a number as its argument and returns an object with an input property.

We then call randomlyFail with a random number generated by Math.random(). The result of the function call is stored in the result variable.

We then check whether the result is successful or not by checking the value of the ok property. If ok is true, then we log the value property to the console. If ok is false, then we log the error property to the console.

Documentation generated from source files by Typedoc.

License

Released under MIT License.