json-tree

Important - this documentation describes a previous version and needs to be updated - however, the tests are up to date and serve as examples until this has been done

Use tree API over JSON-compatible objects

Install

npm install @mojule/json-tree

Example

const JsonTree = require( '@mojule/json-tree' )

const jsonData = require( './test-data.json' )

const tree = JsonTree( jsonData )

const numbers = tree.findAll( node => node.isNumber() )

numbers.forEach( numberNode => {
  const value = node.getValue( 'nodeValue' )

  value *= 2

  node.setValue( 'nodeValue', value )
})

const newData = tree.toJson()

console.log( JSON.stringify( newData, null, 2 ) )

API

Inherits the same API as tree and tree-factory, and adds the following plugins:

toJson

Converts a node back to it's JSON compatible object representation

const objNode = JsonTree( { foo: 'bar' } )

const obj = objNode.toJson()

// { foo: 'bar' }
console.log( obj )

isEmpty

Overrides the default implementation (which always returns false) and returns true if the node represents null, string, number or boolean.

This ensures that trying to add children to any of these nodes will throw an error - see the tree-factory documentation for more details.

const arrayNode = JsonTree( [ 36 ] )
const numNode = JsonTree( 42 )

// OK
arrayNode.add( numNode )

// throws
numNode.add( arrayNode )

slug

Overrides the default implementation so that if a node is a property node, the propertyName is returned instead of the node's index within its parent. This also affects getPath and atPath, as paths are generated from slugs

const objNode = JsonTree( { foo: 'bar' } )
const fooNode = objNode.getProperty( 'foo' )

// 'foo'
console.log( fooNode.slug() )

// '/foo'
console.log( fooNode.getPath() )

Property plugins

Only added to object nodes.

getProperty

Returns the node representing a named property on an object node. Returns undefined if the object does not have the property.

const objNode = JsonTree( { foo: 'bar' } )
const fooNode = objNode.getProperty( 'foo' )

// 'bar'
console.log( fooNode.getValue( 'nodeValue' ) )

setProperty

Sets the named property on the object, replacing it if it already exists

const objNode = JsonTree( { foo: 'bar' } )

objNode.setProperty( 'foo', JsonTree( 'new bar' ) )

const fooNode = objNode.getProperty( 'foo' )

// 'new bar'
console.log( fooPropertyNode.getValue( 'nodeValue' ) )

hasProperty

Returns true if the object has the named property, false if not.

const objNode = JsonTree( { foo: 'bar' } )

// true
console.log( objNode.hasProperty( 'foo' ) )

// false
console.log( objNode.hasProperty( 'nope' ) )

removeProperty

Removes the named property node from the object node. Will throw if the named property does not exist.

const objNode = JsonTree( { foo: 'bar' } )

// true
console.log( objNode.hasProperty( 'foo' ) )

objNode.removeProperty( 'foo' )

// false
console.log( objNode.hasProperty( 'foo' ) )

renameProperty

Renames the named property. Will throw if the named property does not exist.

const objNode = JsonTree( { foo: 'bar' } )

// true
console.log( objNode.hasProperty( 'foo' ) )

objNode.renameProperty( 'foo', 'newFoo' )

// false
console.log( objNode.hasProperty( 'foo' ) )

// true
console.log( objNode.hasProperty( 'newFoo' ) )

keys

Returns a list of all the object node's property names

const objNode = JsonTree( { foo: 'bar', abc: 'xyz' } )

// [ 'foo', 'abc' ]
console.log( objNode.keys() )

values

Returns a list of all the object node's property values

const objNode = JsonTree( { foo: 'bar', abc: 'xyz' } )

// [ 'bar', 'xyz' ]
console.log( objNode.values() )

Type plugins

isObject, isArray, isString, isNumber, isBoolean, isNull

const objNode = JsonTree( { foo: 'bar' } )

// true
console.log( objNode.isObject() )

// false
console.log( objNode.isArray() )