From 35862f8a695b3a142f04997f262a275221edd713 Mon Sep 17 00:00:00 2001
From: Luk Lu <luk.lu@faronear.org>
Date: Sat, 9 Dec 2023 16:04:32 +0800
Subject: [PATCH] u

---
 coretool.js | 13 ++++++++-----
 1 file changed, 8 insertions(+), 5 deletions(-)

diff --git a/coretool.js b/coretool.js
index cfdc93b..07f0b48 100644
--- a/coretool.js
+++ b/coretool.js
@@ -246,7 +246,7 @@ module.exports = {
       : t // 可以是 undefined, boolean, number, string
   },
 
-  read_varchain (path, root) {
+  read_varchain (path, root, emptyValue) {
     let parent = root || globalThis || global || window || {}
     let keychain = path.split('.')
     for (let key of keychain) {
@@ -258,13 +258,13 @@ module.exports = {
         // 支持 myarr[index] 作为一个路径节点
         let [all, arr, index] = key.match(/^(\w+)\[(.*)\]$/)
         parent = parent[arr][parseInt(index)]
-      } else if (typeof parent === 'object' && /^\w+$/.test(key) && typeof parent[key] != 'undefined' && parent[key] != null) {
+      } else if (typeof parent === 'object' && /^\w+$/.test(key) && typeof parent[key] != 'undefined') {
         parent = parent[key]
       } else {
-        return undefined
+        return emptyValue
       }
     }
-    return parent
+    return typeof parent !== 'undefined' ? parent : emptyValue
   },
 
   set_varchain (path, root, value) {
@@ -298,6 +298,9 @@ module.exports = {
   },
 
   number_precision (number, precision = 4) {
-    return Number(Number(number).toFixed(precision))
+    if (isFinite(number)) // null, '', '0', [] 
+      return Number(Number(number).toFixed(precision))
+    else // undefined, NaN, Infinity, {}
+      return 0
   },
 }