Merge pull request #3891 from matrix-org/t3chguy/fix_multi_paragraph_formatting

Fix paragraph-awareness of the composer formatting features

src/editor/deserialize.js

@@ -250,7 +250,7 @@ function parseHtmlMessage(html, partCreator, isQuotedMessage) {
 }
 
 export function parsePlainTextMessage(body, partCreator, isQuotedMessage) {
-    const lines = body.split("\n");
+    const lines = body.split(/\r\n|\r|\n/g); // split on any new-line combination not just \n, collapses \r\n
     const parts = lines.reduce((parts, line, i) => {
         if (isQuotedMessage) {
             parts.push(partCreator.plain(QUOTE_LINE_PREFIX));

src/editor/operations.js

@@ -100,27 +100,71 @@ export function formatRangeAsCode(range) {
     replaceRangeAndExpandSelection(range, parts);
 }
 
+// parts helper methods
+const isBlank = part => !part.text || !/\S/.test(part.text);
+const isNL = part => part.type === "newline";
+
 export function toggleInlineFormat(range, prefix, suffix = prefix) {
     const {model, parts} = range;
     const {partCreator} = model;
 
-    const isFormatted = parts.length &&
-        parts[0].text.startsWith(prefix) &&
-        parts[parts.length - 1].text.endsWith(suffix);
+    // compute paragraph [start, end] indexes
+    const paragraphIndexes = [];
+    let startIndex = 0;
+    // start at i=2 because we look at i and up to two parts behind to detect paragraph breaks at their end
+    for (let i = 2; i < parts.length; i++) {
+        // paragraph breaks can be denoted in a multitude of ways,
+        // - 2 newline parts in sequence
+        // - newline part, plain(<empty or just spaces>), newline part
 
-    if (isFormatted) {
-        // remove prefix and suffix
-        const partWithoutPrefix = parts[0].serialize();
-        partWithoutPrefix.text = partWithoutPrefix.text.substr(prefix.length);
-        parts[0] = partCreator.deserializePart(partWithoutPrefix);
+        // bump startIndex onto the first non-blank after the paragraph ending
+        if (isBlank(parts[i - 2]) && isNL(parts[i - 1]) && !isNL(parts[i]) && !isBlank(parts[i])) {
+            startIndex = i;
+        }
 
-        const partWithoutSuffix = parts[parts.length - 1].serialize();
-        const suffixPartText = partWithoutSuffix.text;
-        partWithoutSuffix.text = suffixPartText.substring(0, suffixPartText.length - suffix.length);
-        parts[parts.length - 1] = partCreator.deserializePart(partWithoutSuffix);
-    } else {
-        parts.unshift(partCreator.plain(prefix));
-        parts.push(partCreator.plain(suffix));
+        // if at a paragraph break, store the indexes of the paragraph
+        if (isNL(parts[i - 1]) && isNL(parts[i])) {
+            paragraphIndexes.push([startIndex, i - 1]);
+            startIndex = i + 1;
+        } else if (isNL(parts[i - 2]) && isBlank(parts[i - 1]) && isNL(parts[i])) {
+            paragraphIndexes.push([startIndex, i - 2]);
+            startIndex = i + 1;
+        }
     }
+
+    const lastNonEmptyPart = parts.map(isBlank).lastIndexOf(false);
+    // If we have not yet included the final paragraph then add it now
+    if (startIndex <= lastNonEmptyPart) {
+        paragraphIndexes.push([startIndex, lastNonEmptyPart + 1]);
+    }
+
+    // keep track of how many things we have inserted as an offset:=0
+    let offset = 0;
+    paragraphIndexes.forEach(([startIndex, endIndex]) => {
+        // for each paragraph apply the same rule
+        const base = startIndex + offset;
+        const index = endIndex + offset;
+
+        const isFormatted = (index - base > 0) &&
+            parts[base].text.startsWith(prefix) &&
+            parts[index - 1].text.endsWith(suffix);
+
+        if (isFormatted) {
+            // remove prefix and suffix
+            const partWithoutPrefix = parts[base].serialize();
+            partWithoutPrefix.text = partWithoutPrefix.text.substr(prefix.length);
+            parts[base] = partCreator.deserializePart(partWithoutPrefix);
+
+            const partWithoutSuffix = parts[index - 1].serialize();
+            const suffixPartText = partWithoutSuffix.text;
+            partWithoutSuffix.text = suffixPartText.substring(0, suffixPartText.length - suffix.length);
+            parts[index - 1] = partCreator.deserializePart(partWithoutSuffix);
+        } else {
+            parts.splice(index, 0, partCreator.plain(suffix)); // splice in the later one first to not change offset
+            parts.splice(base, 0, partCreator.plain(prefix));
+            offset += 2; // offset index to account for the two items we just spliced in
+        }
+    });
+
     replaceRangeAndExpandSelection(range, parts);
 }