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https://github.com/claudijo/level-tier
Minimalistic LevelUP utility for namespacing keys and facilitating blazing fast range queries.
https://github.com/claudijo/level-tier
Last synced: 2 months ago
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Minimalistic LevelUP utility for namespacing keys and facilitating blazing fast range queries.
- Host: GitHub
- URL: https://github.com/claudijo/level-tier
- Owner: claudijo
- License: mit
- Created: 2016-01-09T16:15:44.000Z (about 9 years ago)
- Default Branch: master
- Last Pushed: 2021-12-30T22:13:46.000Z (about 3 years ago)
- Last Synced: 2024-10-06T12:18:43.080Z (3 months ago)
- Language: JavaScript
- Homepage:
- Size: 19.5 KB
- Stars: 1
- Watchers: 4
- Forks: 1
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
- License: LICENSE
Awesome Lists containing this project
- awesome-blazingly-fast - level-tier - Minimalistic LevelUP utility for namespacing keys and facilitating blazing fast range queries. (JavaScript)
README
# level-tier
Minimalistic LevelUP utility for namespacing keys and facilitating blazing fast
range queries.
## Caveat
You might want to zero pad numerical values (such as arbitrary timestamps) to
have a uniform length if using them as parts of a namespaced key. Failing to do
so might result in unexpected ordering, as emphasised by the example below.
`'10' < '2' // -> true`
`'10' < '02' // -> false`
level-tier will warn if using numbers as namespace keys.
## Uniform length timestamp padding
level-tier includes a convenience method `leveltier.now()` that produces uniform length timestamps.
```js
Date.now() // -> 1575146509497
leveltier.now() // -> '00000001575146509497'
```
This function also accepts a timestamp to pad when creating a range Key.
```js
leveltier.now({ timestamp: 1575146509497 }) // -> '00000001575146509497'
```
Putting this together, writing and retrieval would look like this
```js
// writing data
var key = leveltier(['data', leveltier.now()])
mydb.put(key, data)
// retrieving data after some lower bound
var startkey = leveltier.gte(['data', leveltier.now({ timestamp: 1575156550378 })])
mydb.createReadStream({ gt:startkey })
```
## Important note
This module is a minimalistic and naive implementation namespacing
lexicographical keys. It simply uses `\x00` and `\uffff` as lower and upper
bounds. Allowing user input to determine the keys and not stripping out the
delimiter characters could result in the NoSQL equivalent of an SQL injection
attack. For this reason any characters corresponding to the upper or lower bounds
will be stripped from the namespaced keys.
## Other solutions
For a robust solutions when it comes to "binary serialization of arbitrarily complex
structures that sort element-wise", see
[deanlandolt/bytewise](https://github.com/deanlandolt/bytewise).
# Examples
Import the module
```js
const leveltier = require('level-tier')
```
## Creating namespaced key
```js
leveltier(['Alice', 'Cooper']); // -> alice\x00cooper
```
## Creating range start key
The following constructs a start key that can be used as the `gte` option
when creating a read stream in LevelUP.
```js
leveltier.gte(['Alice']); // -> Alice\x00
```
## Creating range end key
The following constructs an end key that can be used as the `lte` option when
creating a read stream in LevelUP.
```js
leveltier.lte(['Alice']); // -> Alice\x00\uffff
```
## Combining start and end keys
Combining `{gte: leveltier.gte(['Alice']), lte: leveltier.lte(['Alice'])}` when creating a read stream
in LevelUP would yield all documents that have "Alice" as the first part in the name spaced key.
## Parsing a key
```js
leveltier.parse('Alice\x00Cooper'); // -> ['Alice', 'Cooper']
```
## Test
Run unit tests;
`$ npm test`
# License
[MIT](LICENSE)