u2x

u2x ·

A suite of utilities for converting unknown data to desired type.

Install

yarn add u2x

or

npm install u2x --save

Background

When you receive data from remote.

const result = await request('...');

You cannot trust that type of data. If you access its property directly, such as:

console.log(result.aaa); // May be thrown.

That may be thrown, if the result is null or undefined.

Therefore, you can wrap u2o with this result, such as

const safeResult = u2o(result);

console.log(safeResult.aaa);

The u2o function convert any value to an object.

Wait! Is not that too simple? So why do not I wrap it with Object?

const safeResult = Object(result);

console.log(safeResult.aaa);

This code works just as well.

Yes, you are right. The u2o function is also implemented using Object, you can see the code src/u2o.ts here.

But, in TypeScript, Object always returns an any, it is a bad practis.

For example

const safeResult = Object(result);

console.log(safeResult.aaa.bbb); // May be throw

On an any, all properties are any (The contagiousness of any), you can not guarantee that every property is an object.

In fact, if Object(...) returns Record<PropertyKey, unknown>, that is a better definition. When you attempt to access a property from an unknown, TypeScript compiler warns you that this is an error.