Filtering collection properties the easy way
Trying to make web faster, more accessible, cheaper to run, more effective:
- Choosing right tool for the job (ie. serverless, static site generator)
- Reducing network utilization by removal, compression, optimization, minification
- Lazyloading/deferring non critical parts
- Optimizing critical path and assets
- Training about impact 3rd party scripts have on the performance
- Pushing minimalism and simplicity philosophy in the team
... and many more contextual decisions.
I have a collection from AWS S3 API that looks like this:
[
{
Key: 'instances/1/assets/12345.assets_deploy.zip',
LastModified: 2019-12-15T17:15:01.000Z,
ETag: '"e9907057481d6ce6fbd5e0d072353b96"',
Size: 169554,
StorageClass: 'STANDARD'
},
{
Key: 'instances/1/assets/12345.big.assets_deploy.zip',
LastModified: 2019-12-15T14:19:25.000Z,
ETag: '"02eb918489c37029e9aa218f5c1bae8e-10"',
Size: 171526382,
StorageClass: 'STANDARD'
}
]
And because I have it on the server-side, and client needs only Key, LastModified and Size information, I need to filter it out before sending it back to the browser.
This is what I came up with:
const body = objects.map(({ Key, LastModified, Size }) => ({ Key, LastModified, Size }));
I found it pretty elegant, maybe because I like symmetry :)
Couple words of explanation:
1) .map - Mapping over each element of an array - in this case objects
2) ({ Key, LastModified, Size }) - Using object destructuring to pull out only required key/value pairs form each object
3) => - Using arrow function to make it shorter
4) Using () around object literal {...} to skip the return keyword
Result is exactly what client expected:
[
{
Key: 'instances/1/assets/12345.assets_deploy.zip',
LastModified: 2019-12-15T17:15:01.000Z,
Size: 169554
},
{
Key: 'instances/1/assets/12345.big.assets_deploy.zip',
LastModified: 2019-12-15T14:19:25.000Z,
Size: 171526382
}
]
Can it be made better?
