memory-level
In-memory abstract-level database for Node.js and browsers, backed by a fully persistent red-black tree. The successor to memdown and level-mem.
📌 Which module should I use? What isabstract-level? Head over to the FAQ.
Usage
If you are upgrading: please see UPGRADING.md.
const { MemoryLevel } = require('memory-level')
// Create a database
const db = new MemoryLevel({ valueEncoding: 'json' })
// Add an entry with key 'a' and value 1
await db.put('a', 1)
// Add multiple entries
await db.batch([{ type: 'put', key: 'b', value: 2 }])
// Get value of key 'a': 1
const value = await db.get('a')
// Iterate entries with keys that are greater than 'a'
for await (const [key, value] of db.iterator({ gt: 'a' })) {
console.log(value) // 2
}
With callbacks:
db.put('example', { hello: 'world' }, (err) => {
if (err) throw err
db.get('example', (err, value) => {
if (err) throw err
console.log(value) // { hello: 'world' }
})
})
API
The API of memory-level follows that of abstract-level with a one additional constructor option (see below). The createIfMissing and errorIfExists options of abstract-level are not relevant here. Data is discarded when the last reference to the database is released (i.e. db = null). Closing or reopening the database has no effect on the data. Data is not copied: when storing a Buffer value for example, subsequent mutations to that Buffer will affect the stored data too.
db = new MemoryLevel([options])
Besides abstract-level options, the optional options object may contain:
storeEncoding(string): one of'buffer','view','utf8'. How to store data internally. This affects which data types can be stored non-destructively. The default is'buffer'(that means Buffer) which is non-destructive. In browsers it may be preferable to use'view'(Uint8Array) to be able to exclude thebuffershim. Or if there's no need to store binary data, then'utf8'(String). Regardless of thestoreEncoding,memory-levelsupports input that is of any of the aforementioned types, but internally converts it to one type in order to provide a consistent sort order.
Install
With npm do:
npm install memory-level
Contributing
Level/memory-level is an OPEN Open Source Project. This means that:
Individuals making significant and valuable contributions are given commit-access to the project to contribute as they see fit. This project is more like an open wiki than a standard guarded open source project.
See the Contribution Guide for more details.
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