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rewrite HTML>MD conversion,handle (nested) block elements&quotes better 

Re-use walkDOMDepthFirst we already had for turning the editor into
a string, which also allows us to detect when leaving a node better,
which is needed to decide how block elements create newline parts
is more centralized and robust manner, more in line with
how html works (consecutive block elements break the line)
instead of hacky special casing from before.

Also, to support every line of MD generated
within a BLOCKQUOTE, the parts an element creates are returned
and then centrally prepended with "> ", instead of passing in
the parts array and doing it in every parse... function.
pull/21833/head
Bruno Windels 2019-05-29 14:46:15 +02:00
parent b0d87e7e47
commit 686045b46a
1 changed files with 156 additions and 82 deletions
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238
src/editor/deserialize.js
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@ -17,32 +17,125 @@ limitations under the License.
import { MATRIXTO_URL_PATTERN } from '../linkify-matrix';
import { PlainPart, UserPillPart, RoomPillPart, NewlinePart } from "./parts";
import { walkDOMDepthFirst } from "./dom";
const REGEX_MATRIXTO = new RegExp(MATRIXTO_URL_PATTERN);
function parseLink(a, parts, room) {
function parseLink(a, room) {
const {href} = a;
const pillMatch = REGEX_MATRIXTO.exec(href) || [];
const resourceId = pillMatch[1]; // The room/user ID
const prefix = pillMatch[2]; // The first character of prefix
switch (prefix) {
case "@":
parts.push(new UserPillPart(
return new UserPillPart(
resourceId,
a.textContent,
room.getMember(resourceId),
));
break;
);
case "#":
parts.push(new RoomPillPart(resourceId));
break;
return new RoomPillPart(resourceId);
default: {
if (href === a.textContent) {
parts.push(new PlainPart(a.textContent));
return new PlainPart(a.textContent);
} else {
parts.push(new PlainPart(`[${a.textContent}](${href})`));
return new PlainPart(`[${a.textContent}](${href})`);
}
break;
}
}
}
function parseCodeBlock(n) {
const parts = [];
const preLines = `\`\`\`\n${n.textContent}\`\`\``.split("\n");
preLines.forEach((l, i) => {
parts.push(new PlainPart(l));
if (i < preLines.length - 1) {
parts.push(new NewlinePart("\n"));
}
});
return parts;
}
function parseElement(n, room) {
switch (n.nodeName) {
case "A":
return parseLink(n, room);
case "BR":
return new NewlinePart("\n");
case "EM":
return new PlainPart(`*${n.textContent}*`);
case "STRONG":
return new PlainPart(`**${n.textContent}**`);
case "PRE":
return parseCodeBlock(n);
case "CODE":
return new PlainPart(`\`${n.textContent}\``);
case "DEL":
return new PlainPart(`<del>${n.textContent}</del>`);
case "LI":
if (n.parentElement.nodeName === "OL") {
return new PlainPart(` 1. `);
} else {
return new PlainPart(` - `);
}
default:
// don't textify block nodes we'll decend into
if (!checkDecendInto(n)) {
return new PlainPart(n.textContent);
}
}
}
function checkDecendInto(node) {
switch (node.nodeName) {
case "PRE":
// a code block is textified in parseCodeBlock
// as we don't want to preserve markup in it,
// so no need to decend into it
return false;
default:
return checkBlockNode(node);
}
}
function checkBlockNode(node) {
switch (node.nodeName) {
case "PRE":
case "BLOCKQUOTE":
case "DIV":
case "P":
case "UL":
case "OL":
case "LI":
return true;
default:
return false;
}
}
function checkIgnored(n) {
if (n.nodeType === Node.TEXT_NODE) {
// riot adds \n text nodes in a lot of places,
// which should be ignored
return n.nodeValue === "\n";
} else if (n.nodeType === Node.ELEMENT_NODE) {
return n.nodeName === "MX-REPLY";
}
return true;
}
function prefixQuoteLines(isFirstNode, parts) {
const PREFIX = "> ";
// a newline (to append a > to) wouldn't be added to parts for the first line
// if there was no content before the BLOCKQUOTE, so handle that
if (isFirstNode) {
parts.splice(0, 0, new PlainPart(PREFIX));
}
for (let i = 0; i < parts.length; i += 1) {
if (parts[i].type === "newline") {
parts.splice(i + 1, 0, new PlainPart(PREFIX));
i += 1;
}
}
}
@ -51,83 +144,64 @@ function parseHtmlMessage(html, room) {
// no nodes from parsing here should be inserted in the document,
// as scripts in event handlers, etc would be executed then.
// we're only taking text, so that is fine
const root = new DOMParser().parseFromString(html, "text/html").body;
let n = root.firstChild;
const rootNode = new DOMParser().parseFromString(html, "text/html").body;
const parts = [];
let isFirstNode = true;
while (n && n !== root) {
switch (n.nodeType) {
case Node.TEXT_NODE:
// the plainpart doesn't accept \n and will cause
// a newlinepart to be created.
if (n.nodeValue !== "\n") {
parts.push(new PlainPart(n.nodeValue));
}
break;
case Node.ELEMENT_NODE:
switch (n.nodeName) {
case "MX-REPLY":
break;
case "DIV":
case "P": {
// block element should cause line break if not first
if (!isFirstNode) {
parts.push(new NewlinePart("\n"));
}
// decend into paragraph or div
if (n.firstChild) {
n = n.firstChild;
continue;
} else {
break;
}
}
case "A": {
parseLink(n, parts, room);
break;
}
case "BR":
parts.push(new NewlinePart("\n"));
break;
case "EM":
parts.push(new PlainPart(`*${n.textContent}*`));
break;
case "STRONG":
parts.push(new PlainPart(`**${n.textContent}**`));
break;
case "PRE": {
// block element should cause line break if not first
if (!isFirstNode) {
parts.push(new NewlinePart("\n"));
}
const preLines = `\`\`\`\n${n.textContent}\`\`\``.split("\n");
preLines.forEach((l, i) => {
parts.push(new PlainPart(l));
if (i < preLines.length - 1) {
parts.push(new NewlinePart("\n"));
}
});
break;
}
case "CODE":
parts.push(new PlainPart(`\`${n.textContent}\``));
break;
case "DEL":
parts.push(new PlainPart(`<del>${n.textContent}</del>`));
break;
default:
parts.push(new PlainPart(n.textContent));
break;
}
break;
let lastNode;
let inQuote = false;
function onNodeEnter(n) {
if (checkIgnored(n)) {
return false;
}
// go up if we can't go next
if (!n.nextSibling) {
n = n.parentElement;
if (n.nodeName === "BLOCKQUOTE") {
inQuote = true;
}
n = n.nextSibling;
isFirstNode = false;
const newParts = [];
if (lastNode && (checkBlockNode(lastNode) || checkBlockNode(n))) {
newParts.push(new NewlinePart("\n"));
}
if (n.nodeType === Node.TEXT_NODE) {
newParts.push(new PlainPart(n.nodeValue));
} else if (n.nodeType === Node.ELEMENT_NODE) {
const parseResult = parseElement(n, room);
if (parseResult) {
if (Array.isArray(parseResult)) {
newParts.push(...parseResult);
} else {
newParts.push(parseResult);
}
}
}
if (newParts.length && inQuote) {
const isFirstPart = parts.length === 0;
prefixQuoteLines(isFirstPart, newParts);
}
parts.push(...newParts);
// extra newline after quote, only if there something behind it...
if (lastNode && lastNode.nodeName === "BLOCKQUOTE") {
parts.push(new NewlinePart("\n"));
}
lastNode = null;
return checkDecendInto(n);
}
function onNodeLeave(n) {
if (checkIgnored(n)) {
return;
}
if (n.nodeName === "BLOCKQUOTE") {
inQuote = false;
}
lastNode = n;
}
walkDOMDepthFirst(rootNode, onNodeEnter, onNodeLeave);
return parts;
}