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Superseded bymemory-level. Please seeFrequently Asked Questions.

If you are upgrading: please seeUPGRADING.md.

constlevelup=require('levelup')constmemdown=require('memdown')constdb=levelup(memdown())db.put('hey','you',(err)=>{if(err)throwerrdb.get('hey',{asBuffer:false},(err,value)=>{if(err)throwerrconsole.log(value)// 'you'})})

Withasync/await:

awaitdb.put('hey','you')constvalue=awaitdb.get('hey',{asBuffer:false})

Your data is discarded when the process ends or you release a reference to the store. Note as well, though the internals ofmemdown operate synchronously -levelup does not.

Keys and values can be strings or Buffers. Any other key type will be irreversibly stringified. The only exceptions arenull andundefined. Keys and values of that type are rejected.

constdb=levelup(memdown())db.put('example',123,(err)=>{if(err)throwerrdb.createReadStream({keyAsBuffer:false,valueAsBuffer:false}).on('data',(entry)=>{console.log(typeofentry.key)// 'string'console.log(typeofentry.value)// 'string'})})

If you desire non-destructive encoding (e.g. to store and retrieve numbers as-is), wrapmemdown withencoding-down. Alternatively installlevel-mem which conveniently bundleslevelup,memdown andencoding-down. Such an approach is also recommended if you want to achieve universal (isomorphic) behavior. For example, you could haveleveldown in a backend andmemdown in the frontend.

constencode=require('encoding-down')constdb=levelup(encode(memdown(),{valueEncoding:'json'}))db.put('example',123,(err)=>{if(err)throwerrdb.createReadStream({keyAsBuffer:false,valueAsBuffer:false}).on('data',(entry)=>{console.log(typeofentry.key)// 'string'console.log(typeofentry.value)// 'number'})})

Amemdown store is backed bya fully persistent data structure and thus has snapshot guarantees. Meaning that reads operate on a snapshot in time, unaffected by simultaneous writes.

In addition to the regularnpm test, you can testmemdown in a browser of choice with:

npm run test-browser-local

To check code coverage:

npm run coverage

Level/memdown is anOPEN 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 theContribution Guide for more details.

Cross-browser Testing Platform and Open Source ♥ Provided bySauce Labs.

Support us with a monthly donation onOpen Collective and help us continue our work.

MIT