fixes

static/js/authorship.js

@@ -91,6 +91,47 @@ export function replaceAuthorshipOwner(model, matcher, replacement, contentLengt
   };
 }
 
+
+export function lineAuthors(content, model) {
+  const starts = [0];
+  for (let i = 0; i < content.length; i++) if (content.charCodeAt(i) === 10) starts.push(i + 1);
+  return starts.map((start, index) => {
+    const end = index + 1 < starts.length ? starts[index + 1] : content.length;
+    const totals = new Map();
+    for (const span of model?.spans || []) {
+      const overlap = Math.max(0, Math.min(end, span.end) - Math.max(start, span.start));
+      if (overlap) totals.set(span.owner, (totals.get(span.owner) || 0) + overlap);
+    }
+    return [...totals.entries()].sort((a, b) => b[1] - a[1]).map(([owner]) => owner);
+  });
+}
+
+export function mapSelectionThroughEdit(previousText, nextText, start, end = start) {
+  if (previousText === nextText) return { start, end };
+  let prefix = 0;
+  const shared = Math.min(previousText.length, nextText.length);
+  while (prefix < shared && previousText.charCodeAt(prefix) === nextText.charCodeAt(prefix)) prefix++;
+
+  let oldSuffix = previousText.length;
+  let newSuffix = nextText.length;
+  while (oldSuffix > prefix && newSuffix > prefix && previousText.charCodeAt(oldSuffix - 1) === nextText.charCodeAt(newSuffix - 1)) {
+    oldSuffix--;
+    newSuffix--;
+  }
+
+  const insertedLength = newSuffix - prefix;
+  const delta = insertedLength - (oldSuffix - prefix);
+  const map = position => {
+    if (position < prefix) return position;
+    if (position > oldSuffix) return position + delta;
+    if (position === prefix && oldSuffix === prefix) return prefix + insertedLength;
+    return prefix + insertedLength;
+  };
+  return {
+    start: Math.max(0, Math.min(nextText.length, map(start))),
+    end: Math.max(0, Math.min(nextText.length, map(end))),
+  };
+}
 export function lineOwners(content, model) {
   const starts = [0];
   for (let i = 0; i < content.length; i++) if (content.charCodeAt(i) === 10) starts.push(i + 1);