string-node

A package for trees where the node values are strings

npm install @mojule/string-node

const StringNode = require( '@mojule/string-node' )

const root = Node( 'Root' )
const child = Node( 'Child' )

root.appendChild( child )

Exactly the same as Node except that it enforces the value being a string (via String( value ) ) and has two static methods, stringify and parse

StringNode.stringify( str )

Creates a string representation of the tree. EOL characters within string nodes are normalized to \n and escaped.

The example data used, as raw nodes

const nodeUtils = require( '@mojule/node-utils' )
const StringNode = require( '@mojule/string-node' )
const data = require( './test/fixtures/biology.json' )

const { deserialize } = nodeUtils

const tree = deserialize( StringNode, data )

console.log( StringNode.stringify( tree ) )

Animalia
  Chordate
    Mammal
      Primate
        Hominidae
          Homo
            Sapiens
              Human
        Pongidae
          Pan
            Troglodytes
              Chimpanzee
      Carnivora
        Felidae
          Felis
            Domestica
              House Cat
            Leo
              Lion
  Arthropoda
    Insect
      Diptera
        Muscidae
          Musca
            Domestica
              Housefly

StringNode.parse

The default behaviour is to take a tree as a string in the format outlined above and returns a root node with child nodes nested as appropriate.

• root must have no indent.
• will throw if there is more than one root or nesting doesn't make sense.
• tabs are converted to two spaces.
• EOL within strings is expected to be escaped, eg \n rather than a literal EOL.
• empty lines are ignored unless the option retainEmpty is passed, see below.

If the deserializeMultiple : true option is set there may be multiple roots in the passed string. Returns an array of root nodes with child nodes nested as appropriate.

const data = `
Root
  Child 1
    Grandchild 1
  Child 2
    Grandchild 2
`

const root = StringNode.parse( data )

// 'Root'
console.log( root.value )

const child = root.firstChild

// 'Child'
console.log( child.value )

// etc.

options

You can pass an optional options parameter. By default it is:

{
  "retainEmpty": false
}

Even with retainEmpty set to true, any leading empty lines are removed, as they cannot have a parent to be added to.

Empty lines between non-empty lines are added at the same level as the next non-empty line.

Empty lines at the end of the data are added at the same level as the previous non-empty line.

The value property of an empty node will be an empty string.

const data = `

Root

  Child 1

    Grandchild 1
  Child 2
    Grandchild 2

`

const root = StringNode.parse( data, { retainEmpty: true } )

console.log( StringNode.stringify( root ).replace( / /g, '.' ) )

Root
..
..Child.1
....
....Grandchild.1
..Child.2
....Grandchild.2
....
....

License

MIT