prosemirror-br-encoded-hierarchy-paragraph

[ CHANGELOG ]

This is a utility module for writing transformations for ProseMirror.

Use this module to interpret leading and trailing line breaks (br) in paragraphs as a hint for levels of a hierarchy. Two line breaks in the middle of a paragraph indicate, that the content at a given position is split into two groups: A leading and a trailing one. If there are several double or multiple line breaks in the middle of the content, only the first one is separating. The others are considered being content.

Motivation

You want a consistent way of transforming back and forth hierarchical structures like nested lists or definition lists to flat paragraphs with line breaks in html.

How it is done

Leading or trailing line breaks are converted to a general structure representing the hierarchical structure. That structure is then used by other modules to establish the according list or definition list nodes (or any other hierarchical node setup) in a ProseMirror document.

Example

An array of BiHrcl is used as general structure to represent the following example test setup:

1. A
2. B
   • x
   • y
3. C

import {schema} from 'prosemirror-schema-basic'
import {builders} from 'prosemirror-test-builder'
import {BiHrcl} from 'prosemirror-br-encoded-hierarchy-base'

const {doc, p, br} = builders(schema, {
  p: {nodeType: 'paragraph'},
	br: {nodeType: 'hard_break'}
})

function t(str, marks) {
	return doc().type.schema.text(str, marks)
}

const setup = [
	new BiHrcl(0, [[t('A')]], []),
	new BiHrcl(0, [[t('B')]], []),
	new BiHrcl(1, [[t('x')]], []),
	new BiHrcl(1, [[t('y')]], []),
	new BiHrcl(0, [[t('C')]], [])
]

The setup is always a flat array, but the depth value - first argument of BiHrcl - makes the hierarchy. In a real use case the nodes are extracted from an actual document by using functions like Node.child, Node.forEach or others.

A more complex example might look like this:

1. A
2. B1
   B2
   ~
   b
   ~

• X
  x
• Y
  y1
  y2

3. C

The ~ represents an empty line.

const setup = [
	new BiHrcl(0, [[t('A')]], []),
	new BiHrcl(0, [[t('B1')], [t('B2')]], [[t('b'), br()]]),
	new BiHrcl(1, [[t('X')]], [[t('x')]]),
	new BiHrcl(1, [[t('Y')]], [[t('y1')],[t('y2')]]),
	new BiHrcl(0, [[t('C')]], [])
]

License

This code is released under an MIT license.