Merge pull request #240 from zh-lx/fix-surname-head

fix: 修复 surname:head 对于复姓开头不生效的问题

Author: zh-lx

lib/common/segmentit/index.ts

@@ -176,7 +176,7 @@ export class AC {
           if (surname === "off") {
             return item.priority !== Priority.Surname;
           } else if (surname === "head") {
-            return i === 0;
+            return item.length - 1 - i === 0;
           } else {
             return true;
           }
@@ -193,7 +193,7 @@ export class AC {
             if (surname === "off") {
               return item.priority !== Priority.Surname;
             } else if (surname === "head") {
-              return i === 0;
+              return item.length - 1 - i === 0;
             } else {
               return true;
             }

test/surname.test.js

@@ -46,4 +46,12 @@ describe("surname", () => {
       "zēng jīng cāng hǎi nán wèi shuǐ hǎo hǎo xué xí lè"
     );
   });
+
+  it("[surname]surname head double", () => {
+    const result = pinyin("令狐冲", { surname: "head" });
+    expect(result).to.be.equal("líng hú chōng");
+
+    const result1 = pinyin("万俟英", { surname: "head" });
+    expect(result1).to.be.equal("mò qí yīng");
+  });
 });