593 lines
19 KiB
JavaScript
593 lines
19 KiB
JavaScript
// Basic parser and formatter for very simple text markup. Mostly targeted at
|
|
// mobile use cases similar to Telegram and WhatsApp.
|
|
//
|
|
// Supports:
|
|
// *abc* -> <b>abc</b>
|
|
// _abc_ -> <i>abc</i>
|
|
// ~abc~ -> <del>abc</del>
|
|
// `abc` -> <tt>abc</tt>
|
|
// Nested frmatting is supported, e.g. *abc _def_* -> <b>abc <i>def</i></b>
|
|
//
|
|
// URLs, @mentions, and #hashtags are extracted and converted into links.
|
|
//
|
|
// JSON data representation is inspired by Draft.js raw formatting.
|
|
|
|
/*
|
|
Text:
|
|
this is *bold*, `code` and _italic_, ~strike~
|
|
combined *bold and _italic_*
|
|
an url: https://www.example.com/abc#fragment and another _www.tinode.co_
|
|
this is a @mention and a #hashtag in a string
|
|
second #hashtag
|
|
|
|
Sample JSON representation of the text above:
|
|
{
|
|
"txt": "this is bold, code and italic, strike combined bold and italic an url: https://www.example.com/abc#fragment " +
|
|
"and another www.tinode.co this is a @mention and a #hashtag in a string second #hashtag",
|
|
"fmt": [
|
|
{ "at":8, "len":4,"tp":"ST" },{ "at":14, "len":4, "tp":"CO" },{ "at":23, "len":6, "tp":"EM"},
|
|
{ "at":31, "len":6, "tp":"DL" },{ "tp":"BR", "len":1, "at":37 },{ "at":56, "len":6, "tp":"EM" },
|
|
{ "at":47, "len":15, "tp":"ST" },{ "tp":"BR", "len":1, "at":62 },{ "at":120, "len":13, "tp":"EM" },
|
|
{ "at":71, "len":36, "key":0 },{ "at":120, "len":13, "key":1 },{ "tp":"BR", "len":1, "at":133 },
|
|
{ "at":144, "len":8, "key":2 },{ "at":159, "len":8, "key":3 },{ "tp":"BR", "len":1, "at":179 },
|
|
{ "at":187, "len":8, "key":3 },{ "tp":"BR", "len":1, "at":195 }
|
|
],
|
|
"refs": [
|
|
{ "tp":"LN", "data":{ "url":"https://www.example.com/abc#fragment" } },
|
|
{ "tp":"LN", "data":{ "url":"http://www.tinode.co" } },
|
|
{ "tp":"MN", "data":{ "val":"mention" } },
|
|
{ "tp":"HT", "data":{ "val":"hashtag" } }
|
|
]
|
|
}
|
|
*/
|
|
|
|
(function(environment) { // closure for web browsers
|
|
'use strict';
|
|
|
|
// Regular expressions for parsing inline formats. Javascript does not support lookbehind,
|
|
// so it's a bit messy.
|
|
var INLINE_STYLES = [
|
|
// Strong = bold, *bold text*
|
|
{name: "ST", start: /(?:^|\W)(\*)[^\s*]/, end: /[^\s*](\*)(?=$|\W)/},
|
|
// Emphesized = italic, _italic text_
|
|
{name: "EM", start: /(?:^|[\W_])(_)[^\s_]/, end: /[^\s_](_)(?=$|[\W_])/},
|
|
// Deleted, ~strike this though~
|
|
{name: "DL", start: /(?:^|\W)(~)[^\s~]/, end: /[^\s~](~)(?=$|\W)/},
|
|
// Code block `this is monospace`
|
|
{name: "CO", start: /(?:^|\W)(`)[^`]/, end: /[^`](`)(?=$|\W)/}
|
|
];
|
|
|
|
// RegExps for entity extraction (RF = reference)
|
|
var ENTITY_TYPES = [
|
|
// URLs
|
|
{name: "LN", dataName: "url",
|
|
pack: function(val) {
|
|
// Check if the protocol is specified, if not use http
|
|
if (!/^[a-z]+:\/\//i.test(val)) {
|
|
val = 'http://' + val;
|
|
}
|
|
return {url: val};
|
|
},
|
|
re: /(https?:\/\/)?(?:www\.)?[-a-zA-Z0-9@:%._\+~#=]{2,256}\.[a-z]{2,4}\b(?:[-a-zA-Z0-9@:%_\+.~#?&//=]*)/g},
|
|
// Mentions @user (must be 2 or more characters)
|
|
{name: "MN", dataName: "val",
|
|
pack: function(val) { return {val: val.slice(1)}; },
|
|
re: /\B@(\w\w+)/g},
|
|
// Hashtags #hashtag
|
|
{name: "HT", dataName: "val",
|
|
pack: function(val) { return {val: val.slice(1)}; },
|
|
re: /\B#(\w\w+)/g}
|
|
];
|
|
|
|
// HTML tag name suggestions
|
|
var HTML_TAGS = {
|
|
ST: { name: 'b', isVoid: false },
|
|
EM: { name: 'i', isVoid: false },
|
|
DL: { name: 'del', isVoid: false },
|
|
CO: { name: 'tt', isVoid: false },
|
|
BR: { name: 'br', isVoid: true },
|
|
LN: { name: 'a', isVoid: false },
|
|
MN: { name: 'a', isVoid: false },
|
|
HT: { name: 'a', isVoid: false }
|
|
};
|
|
|
|
// Helpers for converting Drafty to HTML.
|
|
var DECORATORS = {
|
|
ST: { open: function() { return '<b>'; }, close: function() { return '</b>'; }},
|
|
EM: { open: function() { return '<i>'; }, close: function() { return '</i>'}},
|
|
DL: { open: function() { return '<del>'; }, close: function() { return '</del>'}},
|
|
CO: { open: function() { return '<tt>'; }, close: function() { return '</tt>'}},
|
|
BR: { open: function() { return ''; }, close: function() { return '<br/>'}},
|
|
LN: {
|
|
open: function(data) { return '<a href="' + data.url + '">'; },
|
|
close: function(data) { return '</a>'; },
|
|
props: function(data) { return { href: data.url, target: "_blank" }; },
|
|
},
|
|
MN: {
|
|
open: function(data) { return '<a href="#' + data.val + '">'; },
|
|
close: function(data) { return '</a>'; },
|
|
props: function(data) { return { name: data.val }; },
|
|
},
|
|
HT: {
|
|
open: function(data) { return '<a href="#' + data.val + '">'; },
|
|
close: function(data) { return '</a>'; },
|
|
props: function(data) { return { name: data.val }; },
|
|
}
|
|
};
|
|
|
|
var Drafty = (function() {
|
|
|
|
// Take a string and defined earlier style spans, re-compose them into a tree where each leaf is
|
|
// a same-style (including unstyled) string. I.e. 'hello *bold _italic_* and ~more~ world' ->
|
|
// ('hello ', (b: 'bold ', (i: 'italic')), ' and ', (s: 'more'), ' world');
|
|
//
|
|
// This is needed in order to clear markup, i.e. 'hello *world*' -> 'hello world' and convert
|
|
// ranges from markup-ed offsets to plain text offsets.
|
|
function chunkify(line, start, end, spans) {
|
|
var chunks = [];
|
|
|
|
if (spans.length == 0) {
|
|
return [];
|
|
}
|
|
|
|
for (var i in spans) {
|
|
// Get the next chunk from the queue
|
|
var span = spans[i];
|
|
|
|
// Grab the initial unstyled chunk
|
|
if (span.start > start) {
|
|
chunks.push({text: line.slice(start, span.start)});
|
|
}
|
|
|
|
// Grab the styled chunk. It may include subchunks.
|
|
var chunk = {type: span.type};
|
|
var chld = chunkify(line, span.start + 1, span.end - 1, span.children);
|
|
if (chld.length > 0) {
|
|
chunk.children = chld;
|
|
} else {
|
|
chunk.text = span.text;
|
|
}
|
|
chunks.push(chunk);
|
|
start = span.end + 1; // '+1' is to skip the formatting character
|
|
}
|
|
|
|
// Grab the remaining unstyled chunk, after the last span
|
|
if (start < end) {
|
|
chunks.push({text: line.slice(start, end)});
|
|
}
|
|
|
|
return chunks;
|
|
}
|
|
|
|
// Same as chunkify but used for formatting.
|
|
function forEach(line, start, end, spans, formatter, context) {
|
|
// Add un-styled range before the styled span starts.
|
|
// Process ranges calling formatter for each range.
|
|
var result = [];
|
|
for (var i = 0; i < spans.length; i++) {
|
|
var span = spans[i];
|
|
|
|
// Add un-styled range before the styled span starts.
|
|
if (start < span.at) {
|
|
result.push(formatter.call(context, null, undefined, line.slice(start, span.at)));
|
|
start = span.at;
|
|
}
|
|
// Get all spans which are within current span.
|
|
var subspans = [];
|
|
for (var si = i + 1; si < spans.length && spans[si].at < span.at + span.len; si++) {
|
|
subspans.push(spans[si]);
|
|
i = si;
|
|
}
|
|
|
|
var tag = HTML_TAGS[span.tp] || {};
|
|
result.push(formatter.call(context, span.tp, span.data,
|
|
tag.isVoid ? null : forEach(line, start, span.at + span.len, subspans, formatter, context)));
|
|
|
|
start = span.at + span.len;
|
|
}
|
|
|
|
// Add the last unformatted range.
|
|
if (start < end) {
|
|
result.push(formatter.call(context, null, undefined, line.slice(start, end)));
|
|
}
|
|
|
|
return result;
|
|
}
|
|
|
|
// Detect starts and ends of formatting spans. Unformatted spans are
|
|
// ignored at this stage.
|
|
function spannify(original, re_start, re_end, type) {
|
|
var result = [];
|
|
var index = 0;
|
|
var line = original.slice(0); // make a copy;
|
|
|
|
while (line.length > 0) {
|
|
// match[0]; // match, like '*abc*'
|
|
// match[1]; // match captured in parenthesis, like 'abc'
|
|
// match['index']; // offset where the match started.
|
|
|
|
// Find the opening token.
|
|
var start = re_start.exec(line);
|
|
if (start == null) {
|
|
break;
|
|
}
|
|
|
|
// Because javascript RegExp does not support lookbehind, the actual offset may not point
|
|
// at the markup character. Find it in the matched string.
|
|
var start_offset = start['index'] + start[0].lastIndexOf(start[1]);
|
|
// Clip the processed part of the string.
|
|
line = line.slice(start_offset + 1);
|
|
// start_offset is an offset within the clipped string. Convert to original index.
|
|
start_offset += index;
|
|
// Index now point to the beginning of 'line' within the 'original' string.
|
|
index = start_offset + 1;
|
|
|
|
// Find the matching closing token.
|
|
var end = re_end ? re_end.exec(line) : null;
|
|
if (end == null) {
|
|
break;
|
|
}
|
|
var end_offset = end['index'] + end[0].indexOf(end[1]);
|
|
// Clip the processed part of the string.
|
|
line = line.slice(end_offset + 1);
|
|
// Update offsets
|
|
end_offset += index;
|
|
// Index now point to the beginning of 'line' within the 'original' string.
|
|
index = end_offset + 1;
|
|
|
|
result.push({
|
|
text: original.slice(start_offset+1, end_offset),
|
|
children: [],
|
|
start: start_offset,
|
|
end: end_offset,
|
|
type: type
|
|
});
|
|
}
|
|
|
|
return result;
|
|
}
|
|
|
|
// Convert linear array or spans into a tree representation.
|
|
// Keep standalone and nested spans, throw away partially overlapping spans.
|
|
function toTree(spans) {
|
|
if (spans.length == 0) {
|
|
return [];
|
|
}
|
|
|
|
var tree = [spans[0]];
|
|
var last = spans[0];
|
|
for (var i = 1; i < spans.length; i++) {
|
|
// Keep spans which start after the end of the previous span or those which
|
|
// are complete within the previous span.
|
|
|
|
if (spans[i].start > last.end) {
|
|
// Span is completely outside of the previous span.
|
|
tree.push(spans[i]);
|
|
last = spans[i];
|
|
} else if (spans[i].end < last.end) {
|
|
// Span is fully inside of the previous span. Push to subnode.
|
|
last.children.push(spans[i]);
|
|
}
|
|
// Span could partially overlap, ignoring it as invalid.
|
|
}
|
|
|
|
// Recursively rearrange the subnodes.
|
|
for (var i in tree) {
|
|
tree[i].children = toTree(tree[i].children);
|
|
}
|
|
|
|
return tree;
|
|
}
|
|
|
|
// Get a list of entities from a text.
|
|
function extractEntities(line) {
|
|
var match;
|
|
var extracted = [];
|
|
ENTITY_TYPES.map(function(ent) {
|
|
while ((match = ent.re.exec(line)) !== null) {
|
|
extracted.push({
|
|
offset: match['index'],
|
|
len: match[0].length,
|
|
unique: match[0],
|
|
data: ent.pack(match[0]),
|
|
type: ent.name});
|
|
}
|
|
});
|
|
|
|
if (extracted.length == 0) {
|
|
return extracted;
|
|
}
|
|
|
|
// Remove entities detected inside other entities, like #hashtag in a URL.
|
|
extracted.sort(function(a,b) {
|
|
return a.offset - b.offset;
|
|
});
|
|
|
|
var idx = -1;
|
|
extracted = extracted.filter(function(el) {
|
|
var result = (el.offset > idx);
|
|
idx = el.offset + el.len;
|
|
return result;
|
|
});
|
|
|
|
return extracted;
|
|
}
|
|
|
|
// Convert the chunks into format suitable for serialization.
|
|
function draftify(chunks, startAt) {
|
|
var plain = "";
|
|
var ranges = [];
|
|
for (var i in chunks) {
|
|
var chunk = chunks[i];
|
|
if (!chunk.text) {
|
|
var drafty = draftify(chunk.children, plain.length + startAt);
|
|
chunk.text = drafty.txt;
|
|
ranges = ranges.concat(drafty.fmt);
|
|
}
|
|
|
|
if (chunk.type) {
|
|
ranges.push({at: plain.length + startAt, len: chunk.text.length, tp: chunk.type});
|
|
}
|
|
|
|
plain += chunk.text;
|
|
}
|
|
return {txt: plain, fmt: ranges};
|
|
}
|
|
|
|
// Splice two strings: insert second string into the first one at the given index
|
|
function splice(src, at, insert) {
|
|
return src.slice(0, at) + insert + src.slice(at);
|
|
}
|
|
|
|
return {
|
|
/**
|
|
* Parse text into structured representation.
|
|
*/
|
|
parse: function(content) {
|
|
// Split text into lines. It makes further processing easier.
|
|
var lines = content.split(/\r?\n/);
|
|
|
|
// Holds entities referenced from text
|
|
var entityMap = [];
|
|
var entityIndex = {};
|
|
|
|
// Processing lines one by one, hold intermediate result in blx.
|
|
var blx = [];
|
|
lines.map(function(line) {
|
|
var spans = [];
|
|
var entities = [];
|
|
|
|
// Find formatted spans in the string.
|
|
// Try to match each style.
|
|
INLINE_STYLES.map(function(style) {
|
|
// Each style could be matched multiple times.
|
|
spans = spans.concat(spannify(line, style.start, style.end, style.name));
|
|
});
|
|
|
|
var block;
|
|
if (spans.length == 0) {
|
|
block = {txt: line};
|
|
} else {
|
|
// Sort spans by style occurence early -> late
|
|
spans.sort(function(a,b) {
|
|
return a.start - b.start;
|
|
});
|
|
|
|
// Convert an array of possibly overlapping spans into a tree
|
|
spans = toTree(spans);
|
|
|
|
// Build a tree representation of the entire string, not
|
|
// just the formatted parts.
|
|
var chunks = chunkify(line, 0, line.length, spans);
|
|
|
|
var drafty = draftify(chunks, 0);
|
|
|
|
block = {txt: drafty.txt, fmt: drafty.fmt};
|
|
}
|
|
|
|
// Extract entities from the cleaned up string.
|
|
entities = extractEntities(block.txt);
|
|
if (entities.length > 0) {
|
|
var ranges = [];
|
|
for (var i in entities) {
|
|
// {offset: match['index'], unique: match[0], len: match[0].length, data: ent.packer(), type: ent.name}
|
|
var ent = entities[i];
|
|
var index = entityIndex[ent.unique];
|
|
if (!index) {
|
|
index = entityMap.length;
|
|
entityIndex[ent.unique] = index;
|
|
entityMap.push({tp: ent.type, data: ent.data});
|
|
}
|
|
ranges.push({at: ent.offset, len: ent.len, key: index});
|
|
}
|
|
block.ent = ranges;
|
|
}
|
|
|
|
blx.push(block);
|
|
});
|
|
|
|
var result = {txt: ""};
|
|
|
|
// Merge lines and save line breaks as BR inline formatting.
|
|
if (blx.length > 0) {
|
|
result.txt = blx[0].txt;
|
|
result.fmt = (blx[0].fmt || []).concat(blx[0].ent || []);
|
|
|
|
for (var i = 1; i<blx.length; i++) {
|
|
var block = blx[i];
|
|
var offset = result.txt.length + 1;
|
|
|
|
result.fmt.push({tp: "BR", len: 1, at: offset - 1});
|
|
|
|
result.txt += " " + block.txt;
|
|
if (block.fmt) {
|
|
result.fmt = result.fmt.concat(block.fmt.map(function(s) {
|
|
s.at += offset; return s;
|
|
}));
|
|
}
|
|
if (block.ent) {
|
|
result.fmt = result.fmt.concat(block.ent.map(function(s) {
|
|
s.at += offset; return s;
|
|
}));
|
|
}
|
|
}
|
|
|
|
if (result.fmt.length == 0) {
|
|
delete result.fmt;
|
|
}
|
|
|
|
if (entityMap.length > 0) {
|
|
result.refs = entityMap;
|
|
}
|
|
}
|
|
return result;
|
|
},
|
|
|
|
/**
|
|
* Given the structured representation of rich text, convert it to HTML.
|
|
* No attempt is made to strip pre-existing html markup.
|
|
* This is potentially unsafe because block.txt may contain malicious
|
|
* markup.
|
|
*
|
|
* @param {drafy} content - structured representation of rich text.
|
|
*
|
|
* @return HTML-representation of content
|
|
*/
|
|
unsafeToHTML: function(content) {
|
|
var {txt, fmt, refs} = content;
|
|
|
|
var markup = [];
|
|
if (fmt) {
|
|
for (var i in fmt) {
|
|
var range = fmt[i];
|
|
var tp = range.tp, data;
|
|
if (!tp) {
|
|
var entity = refs[range.key];
|
|
if (entity) {
|
|
tp = entity.tp;
|
|
data = entity.data;
|
|
}
|
|
}
|
|
|
|
if (DECORATORS[tp]) {
|
|
markup.push({idx: range.at, what: DECORATORS[tp].open(data)});
|
|
markup.push({idx: range.at + range.len, what: DECORATORS[tp].close(data)});
|
|
}
|
|
}
|
|
}
|
|
|
|
markup.sort(function(a, b) {
|
|
return b.idx - a.idx; // in descending order
|
|
});
|
|
|
|
for (var i in markup) {
|
|
if (markup[i].what) {
|
|
txt = splice(txt, markup[i].idx, markup[i].what);
|
|
}
|
|
}
|
|
|
|
return txt;
|
|
},
|
|
|
|
/**
|
|
* Transform using custom formatting.
|
|
*
|
|
* @param {Drafty} content - content to transform.
|
|
* @param {function} formatter - callback which transforms individual elements
|
|
* @param {Object} context - context provided to formatter as 'this'.
|
|
*
|
|
* @return {Object} context
|
|
*/
|
|
format: function(content, formatter, context) {
|
|
var {txt, fmt, refs} = content;
|
|
|
|
if (!fmt) {
|
|
return [txt];
|
|
}
|
|
|
|
var spans = [].concat(fmt);
|
|
|
|
// Soft spans first by start index (asc) then by length (desc).
|
|
spans.sort(function(a, b) {
|
|
if (a.at - b.at == 0) {
|
|
return b.len - a.len; // longer one comes first (<0)
|
|
}
|
|
return a.at - b.at;
|
|
});
|
|
|
|
// Denormalize entities into spans. Create a copy of the objects to leave
|
|
// original Drafty object unchanged.
|
|
spans = spans.map(function(s) {
|
|
var data;
|
|
var tp = s.tp;
|
|
if (s.key + 1 > 0) {
|
|
data = refs[s.key].data;
|
|
tp = refs[s.key].tp;
|
|
}
|
|
return {tp: tp, data: data, at: s.at, len: s.len};
|
|
});
|
|
|
|
return forEach(txt, 0, txt.length, spans, formatter, context);
|
|
},
|
|
|
|
/**
|
|
* Given structured representation of rich text, convert it to plain text.
|
|
*
|
|
* @param {drafty} content - content to convert to plain text.
|
|
*/
|
|
toPlainText: function(content) {
|
|
return content.text;
|
|
},
|
|
|
|
/**
|
|
* Returns true if content has no markup and no entities.
|
|
*
|
|
* @param {drafty} content - content to check for presence of markup.
|
|
* @returns true is content is plain text, false otherwise.
|
|
*/
|
|
isPlainText: function(content, noLineBreaks) {
|
|
return !(content.fmt || content.refs);
|
|
},
|
|
|
|
/**
|
|
* Get HTML tag for a given two-letter style name
|
|
* @param {string} style - two-letter style, like ST or LN
|
|
* @returns
|
|
*/
|
|
tagName: function(style) {
|
|
return HTML_TAGS[style] ? HTML_TAGS[style].name : undefined;
|
|
},
|
|
|
|
/**
|
|
* For a given data bundle generate an object with HTML attributes,
|
|
* for instance, given {url: "http://www.example.com/"} return
|
|
* {href: "http://www.example.com/"}
|
|
* @param {stting} style - tw-letter style to generate attributes for.
|
|
* @param {Object} data - data bundle to convert to attributes
|
|
* @returns object with HTML attributes.
|
|
*/
|
|
attrValue: function(style, data) {
|
|
if (data && DECORATORS[style]) {
|
|
return DECORATORS[style].props(data);
|
|
}
|
|
|
|
return undefined;
|
|
},
|
|
|
|
/**
|
|
* Content MIME type.
|
|
* @returns string suitabe for HTTP Content-Type field.
|
|
*/
|
|
getContentType: function() {
|
|
return "text/x-drafty";
|
|
}
|
|
|
|
};
|
|
});
|
|
|
|
// Export for the window object or node; Check that is not already defined.
|
|
if (typeof(environment.Drafty) === 'undefined') {
|
|
environment.Drafty = Drafty();
|
|
}
|
|
})(this); // 'this' will be a window object for the browsers.
|