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88 lines
5.0 KiB
Markdown
88 lines
5.0 KiB
Markdown
Guide to data types used by the Slate-based Rich Text Editor
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------------------------------------------------------------
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We always store the Slate editor state in its Value form.
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The schema for the Value is the same whether the editor is in MD or rich text mode, and is currently (rather arbitrarily)
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dictated by the schema expected by slate-md-serializer, simply because it was the only bit of the pipeline which
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has opinions on the schema. (slate-html-serializer lets you define how to serialize whatever schema you like).
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The BLOCK_TAGS and MARK_TAGS give the mapping from HTML tags to the schema's node types (for blocks, which describe
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block content like divs, and marks, which describe inline formatted sections like spans).
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We use <p/> as the parent tag for the message (XXX: although some tags are technically not allowed to be nested within p's)
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Various conversions are performed as content is moved between HTML, MD, and plaintext representations of HTML and MD.
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The primitives used are:
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* Markdown.js - models commonmark-formatted MD strings (as entered by the composer in MD mode)
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* toHtml() - renders them to HTML suitable for sending on the wire
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* isPlainText() - checks whether the parsed MD contains anything other than simple text.
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* toPlainText() - renders MD to plain text in order to remove backslashes. Only works if the MD is already plaintext (otherwise it just emits HTML)
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* slate-html-serializer
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* converts Values to HTML (serialising) using our schema rules
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* converts HTML to Values (deserialising) using our schema rules
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* slate-md-serializer
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* converts rich Values to MD strings (serialising) but using a non-commonmark generic MD dialect.
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* This should use commonmark, but we use the serializer here for expedience rather than writing a commonmark one.
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* slate-plain-serializer
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* converts Values to plain text strings (serialising them) by concatenating the strings together
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* converts Values from plain text strings (deserialiasing them).
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* Used to initialise the editor by deserializing "" into a Value. Apparently this is the idiomatic way to initialise a blank editor.
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* Used (as a bodge) to turn a rich text editor into a MD editor, when deserialising the converted MD string of the editor into a value
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* PlainWithPillsSerializer
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* A fork of slate-plain-serializer which is aware of Pills (hence the name) and Emoji.
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* It can be configured to output Pills as:
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* "plain": Pills are rendered via their 'completion' text - e.g. 'Matthew'; used for sending messages)
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* "md": Pills are rendered as MD, e.g. [Matthew](https://matrix.to/#/@matthew:matrix.org) )
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* "id": Pills are rendered as IDs, e.g. '@matthew:matrix.org' (used for authoring / commands)
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* Emoji nodes are converted to inline utf8 emoji.
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The actual conversion transitions are:
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* Quoting:
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* The message being quoted is taken as HTML
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* ...and deserialised into a Value
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* ...and then serialised into MD via slate-md-serializer if the editor is in MD mode
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* Roundtripping between MD and rich text editor mode
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* From MD to richtext (mdToRichEditorState):
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* Serialise the MD-format Value to a MD string (converting pills to MD) with PlainWithPillsSerializer in 'md' mode
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* Convert that MD string to HTML via Markdown.js
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* Deserialise that Value to HTML via slate-html-serializer
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* From richtext to MD (richToMdEditorState):
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* Serialise the richtext-format Value to a MD string with slate-md-serializer (XXX: this should use commonmark)
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* Deserialise that to a plain text value via slate-plain-serializer
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* Loading history in one format into an editor which is in the other format
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* Uses the same functions as for roundtripping
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* Scanning the editor for a slash command
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* If the editor is a single line node starting with /, then serialize it to a string with PlainWithPillsSerializer in 'id' mode
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So that pills get converted to IDs suitable for commands being passed around
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* Sending messages
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* In RT mode:
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* If there is rich content, serialize the RT-format Value to HTML body via slate-html-serializer
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* Serialize the RT-format Value to the plain text fallback via PlainWithPillsSerializer in 'plain' mode
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* In MD mode:
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* Serialize the MD-format Value into an MD string with PlainWithPillsSerializer in 'md' mode
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* Parse the string with Markdown.js
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* If it contains no formatting:
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* Send as plaintext (as taken from Markdown.toPlainText())
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* Otherwise
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* Send as HTML (as taken from Markdown.toHtml())
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* Serialize the RT-format Value to the plain text fallback via PlainWithPillsSerializer in 'plain' mode
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* Pasting HTML
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* Deserialize HTML to a RT Value via slate-html-serializer
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* In RT mode, insert it straight into the editor as a fragment
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* In MD mode, serialise it to an MD string via slate-md-serializer and then insert the string into the editor as a fragment.
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The various scenarios and transitions could be drawn into a pretty diagram if one felt the urge, but hopefully the above
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gives sufficient detail on how it's all meant to work. |