@@ -1717,9 +1717,9 @@ var JSONResponse = {
               target.sort = sort = sort == null || srt === sort ? srt : (sort.includes(srt) ? sort : (srt === '=' ? sort + '=' : ''));
             }
 
-            if (isStr && same !== '' && StringUtil.isNotEmpty(first) && StringUtil.isNotEmpty(last)) {
-              var sm = StringUtil.longestSubstr(first, last);
-              target.same = same = StringUtil.longestSubstr(same, sm);
+            if (isStr && same !== '' && (StringUtil.isNotEmpty(first) || StringUtil.isNotEmpty(last))) {
+              var sm = StringUtil.isEmpty(first) ? last : (StringUtil.isEmpty(last) ? first : StringUtil.longestSubstr(first, last));
+              target.same = same = same == null ? sm : (StringUtil.isEmpty(sm) ? same : StringUtil.longestSubstr(same, sm));
             }
           }
         }
@@ -1793,7 +1793,7 @@ var JSONResponse = {
           }
 
           if (isStr && same !== '' && StringUtil.isNotEmpty(real)) {
-            var sm = StringUtil.isEmpty(same) ? real : StringUtil.longestSubstr(real, same); // preReal);
+            var sm = same == null ? real : StringUtil.longestSubstr(real, same); // preReal);
             target.same = same = sm; // StringUtil.longestSubstr(same, sm);
           }
         }
 
@@ -881,12 +881,15 @@ var StringUtil = {
   },
 
   longestSubstr: function(str1, str2, trim) {
-    if (! str1 || ! str2) {
-      return "";
+    let m = StringUtil.isString(str1) ? StringUtil.length(str1, trim) : 0;
+    let n = m <= 0 || ! StringUtil.isString(str2) ? 0 : StringUtil.length(str2, trim);
+    if (n <= 0) {
+      return '';
     }
 
-    let m = StringUtil.length(str1, trim);
-    let n = StringUtil.length(str2, trim);
+    if (str1 === str2) {
+      return StringUtil.get(str1);
+    }
 
     // 创建一个二维数组，dp[i][j] 记录以 str1[i-1] 和 str2[j-1] 结尾的公共子串长度
     let dp = Array.from(Array(m + 1), () => Array(n + 1).fill(0));
Original file line number	Diff line number	Diff line change
`@@ -1717,9 +1717,9 @@ var JSONResponse = {`
`1717`	`1717`	`target.sort = sort = sort == null \|\| srt === sort ? srt : (sort.includes(srt) ? sort : (srt === '=' ? sort + '=' : ''));`
`1718`	`1718`	`}`
`1719`	`1719`
`1720`		`- if (isStr && same !== '' && StringUtil.isNotEmpty(first) && StringUtil.isNotEmpty(last)) {`
`1721`		`- var sm = StringUtil.longestSubstr(first, last);`
`1722`		`- target.same = same = StringUtil.longestSubstr(same, sm);`
	`1720`	`+ if (isStr && same !== '' && (StringUtil.isNotEmpty(first) \|\| StringUtil.isNotEmpty(last))) {`
	`1721`	`+ var sm = StringUtil.isEmpty(first) ? last : (StringUtil.isEmpty(last) ? first : StringUtil.longestSubstr(first, last));`
	`1722`	`+ target.same = same = same == null ? sm : (StringUtil.isEmpty(sm) ? same : StringUtil.longestSubstr(same, sm));`
`1723`	`1723`	`}`
`1724`	`1724`	`}`
`1725`	`1725`	`}`
`@@ -1793,7 +1793,7 @@ var JSONResponse = {`
`1793`	`1793`	`}`
`1794`	`1794`
`1795`	`1795`	`if (isStr && same !== '' && StringUtil.isNotEmpty(real)) {`
`1796`		`- var sm = StringUtil.isEmpty(same) ? real : StringUtil.longestSubstr(real, same); // preReal);`
	`1796`	`+ var sm = same == null ? real : StringUtil.longestSubstr(real, same); // preReal);`
`1797`	`1797`	`target.same = same = sm; // StringUtil.longestSubstr(same, sm);`
`1798`	`1798`	`}`
`1799`	`1799`	`}`