---
Title: Destructuring with True Myth 1.3+
Subtitle: A thing I didn't even realize I could do until after I published it.
Date: 2018-05-19 12:20
Tags: [functional programming, typescript, open source software, libraries, true myth]
Summary: >
Making the value and error properties available means you can now use destructuring.
---
I just realized a neat capability that [True Myth 1.3+](#) unlocks: you can now use destructuring of the `value` property on `Just` and `Result` and the `error` property on `Error` instances.
With `Maybe` instances:
```ts
import Maybe, { just, nothing, isJust } from 'true-myth/maybe';
const maybeStrings: Maybe[] =
[just('hello'), nothing(), just('bye'), nothing()];
const lengths = maybeStrings
.filter(Maybe.isJust)
.map(({ value }) => value.length);
```
With `Result` instances:
```ts
import Result, { ok, err } from 'true-myth/result';
const results: Result[] =
[ok(12), err('wat'), err('oh teh noes'), ok(42)];
const okDoubles = results
.filter(Result.isOk)
.map(({ value }) => value * 2);
const errLengths = results
.filter(Result.isErr)
.map(({ error }) => error.length);
```
None of this is especially novel or anything. It was just a neat thing to realize after the fact, because it wasn’t something I had in mind when I was making these changes! [^1]
[^1]: This was a very strange experience. There’s nothing quite like learning something about a library *you wrote*.