subgraph
v2.1.0
Published
Content addressable graph where every node has at most a single link to another node
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subgraph
Content addressable graph where every node has at most a single link to another node
npm install subgraph
Usage
var subgraph = require('subgraph')
var sg = subgraph(levelupInstance)
var ws = sg.createAppendStream()
ws.write('hello')
ws.write('world')
ws.end(function () {
var rs = sg.createReadStream(ws.key)
rs.on('data', function (node) {
console.log(node) // first {value: 'world'} then {value: 'hello'}
})
})
API
var sg = subgraph(levelupInstance, [options])
Create a new subgraph instance. Options include:
{
prefix: 'optional-sublevel-prefix'
}
var ws = sg.createAppendStream([link])
Create an append stream. The values you write to it will be linked together.
When the stream emits finish
it will have a .key
property that contains the latest link
and a .length
property that contains the number of nodes written
Optionally you can provide a link
in the constructor for the first node to append to.
var rs = sg.createReadStream(key)
Create a read stream from a key. Will read out values in reverse order of writes to the append stream.
var ws = sg.createWriteStream(key)
Create a write stream from a key. Will verify that the values written matches the key when hashed.
sg.add(link, value, [cb])
Shorthand for only adding a single value
sg.get(key, cb)
Shorthand for getting a single value
sg.root(key, cb)
Returns the root of a stream. If a write stream was ended prematurely / destroyed the root returned will have a link property.
sg.root(someKey, function (err, node) {
console.log('root is', node)
console.log('the stream is partially written?', !!root.link)
})
License
MIT