fix(mp): previewImage currentIndex

src/platforms/mp-baidu/service/api/protocols.js

+import normalizePreviewImageArgs from '../../../mp-weixin/helpers/normalize-preview-image-args'
 // 不支持的 API 列表
 const todos = [
   'hideKeyboard',
@@ -60,14 +61,7 @@ const protocols = {
   },
   previewImage: {
     args (fromArgs) {
-      // 处理传入索引值的情况
-      const currentIndex = Number(fromArgs.current)
-      if (!isNaN(currentIndex)) {
-        const urls = fromArgs.urls && Array.isArray(fromArgs.urls) ? fromArgs.urls.concat() : []
-        fromArgs.urls = urls.filter((item, index) => {
-          return index < currentIndex ? item !== urls[currentIndex] : true
-        })
-      }
+      normalizePreviewImageArgs(fromArgs)
       return {
         indicator: false,
         loop: false

src/platforms/mp-toutiao/service/api/protocols.js

+import normalizePreviewImageArgs from '../../../mp-weixin/helpers/normalize-preview-image-args'
+
 // 不支持的 API 列表
 const todos = [
   'hideKeyboard',
@@ -93,14 +95,7 @@ const protocols = {
   },
   previewImage: {
     args (fromArgs) {
-      // 处理传入索引值的情况
-      const currentIndex = Number(fromArgs.current)
-      if (!isNaN(currentIndex)) {
-        const urls = fromArgs.urls && Array.isArray(fromArgs.urls) ? fromArgs.urls.concat() : []
-        fromArgs.urls = urls.filter((item, index) => {
-          return index < currentIndex ? item !== urls[currentIndex] : true
-        })
-      }
+      normalizePreviewImageArgs(fromArgs)
       return {
         indicator: false,
         loop: false

src/platforms/mp-weixin/helpers/normalize-preview-image-args.js

+export default function normalize (fromArgs) {
+  let currentIndex = parseInt(fromArgs.current)
+  if (isNaN(currentIndex)) {
+    return
+  }
+  const urls = fromArgs.urls
+  if (!Array.isArray(urls)) {
+    return
+  }
+  const len = urls.length
+  if (!len) {
+    return
+  }
+  if (currentIndex < 0) {
+    currentIndex = 0
+  } else if (currentIndex >= len) {
+    currentIndex = len - 1
+  }
+  if (currentIndex > 0) {
+    fromArgs.current = urls[currentIndex]
+    fromArgs.urls = urls.filter(
+      (item, index) => index < currentIndex ? item !== urls[currentIndex] : true
+    )
+  } else {
+    fromArgs.current = urls[0]
+  }
+}

src/platforms/mp-weixin/service/api/protocols.js

-export const protocols = {
-  previewImage: {
-    args (fromArgs) {
-      // 处理传入索引值的情况
-      const currentIndex = Number(fromArgs.current)
-      if (!isNaN(currentIndex)) {
-        const urls = fromArgs.urls && Array.isArray(fromArgs.urls) ? fromArgs.urls.concat() : []
-        fromArgs.urls = urls.filter((item, index) => {
-          return index < currentIndex ? item !== urls[currentIndex] : true
-        })
-      }
-    }
-  }
-}
-export const todos = []
+import normalizePreviewImageArgs from '../../helpers/normalize-preview-image-args'
+export const protocols = {
+  previewImage: {
+    args: normalizePreviewImageArgs
+  }
+}
+export const todos = []
 export const canIUses = []