@ipld/iq
v0.4.3
Published
## IPLD Query
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Keywords
Readme
EXPERIMENTAL: do not use in production.
IPLD Query
Simplified interface for IPLD graph reading and manipulation.
let iq = require('@ipld/iq')
let Block = require('@ipld/block')
let block = Block.encoder({one: {two: {three: 'hello world'}}})
let string = await iq(block, 'one/two/three').toString()
// hello world
Configuring Storage
Read-only example:
/* configure a read interface connected to storage */
let store = {}
let get = cid => store[cid.toString()] || null
iq.config.get = get
let block = Block.encoder({one: {two: {three: 'hello world'}}})
let cid = await block.cid()
store[cid.toString()] = block
let string = await iq(`${cid.toString()}/one/two/three`).toString()
// hello world
API
Read APIs
query.value()
Returns a decoded "kind." Best effort is made to determine the kind from composite types.
TODO: Implement some kind of configurable "max size" for composite types which may be prohibitively expensive to pull into memory.
query.toString([joiner='\n'])
Returns any string values from the expression.
If multiple values are found the joiner string is be used to join them into a single string.
Example at top of README.
query.read([start, end])
.read(0, 12)
reads the path value from 0 to the 15th byte..read(5)
reads from the 5th byte.
Full example:
let block = Block.encoder({one: {two: {three: Buffer.from('hello world')}}})
let buffer = await iq(block, 'one/two/three').read()
// Buffer containing 'hello world'
Buffer.isBuffer(buffer)
// true