fix(fix number to column title bug): if column title is big , it will show undefined

rewrite ABCatNum and chatatABC method  in  util.js

src/utils/util.js

@@ -117,70 +117,108 @@ function rgbTohex(color) {
 };
 
 //列下标  字母转数字
-function ABCatNum(abc) {
+function ABCatNum(a) {
-    abc = abc.toUpperCase();
+    // abc = abc.toUpperCase();
 
-    let abc_len = abc.length;
+    // let abc_len = abc.length;
-    if (abc_len == 0) {
+    // if (abc_len == 0) {
-        return NaN;
+    //     return NaN;
-    }
+    // }
 
-    let abc_array = abc.split("");
+    // let abc_array = abc.split("");
-    let wordlen = columeHeader_word.length;
+    // let wordlen = columeHeader_word.length;
-    let ret = 0;
+    // let ret = 0;
 
-    for (let i = abc_len - 1; i >= 0; i--) {
+    // for (let i = abc_len - 1; i >= 0; i--) {
-        if (i == abc_len - 1) {
+    //     if (i == abc_len - 1) {
-            ret += columeHeader_word_index[abc_array[i]];
+    //         ret += columeHeader_word_index[abc_array[i]];
-        }
+    //     }
-        else {
+    //     else {
-            ret += Math.pow(wordlen, abc_len - i - 1) * (columeHeader_word_index[abc_array[i]] + 1);
+    //         ret += Math.pow(wordlen, abc_len - i - 1) * (columeHeader_word_index[abc_array[i]] + 1);
+    //     }
+    // }
+
+    // return ret;
+    if(a==null || a.length==0){
+        return NaN;
     }
+    var str=a.toLowerCase().split("");
+    var num=0;
+    var al = str.length;
+    var getCharNumber = function(charx){
+        return charx.charCodeAt() -96;
+    };
+    var numout = 0;
+    var charnum = 0;
+    for(var i = 0; i < al; i++){
+        charnum = getCharNumber(str[i]);
+        numout += charnum * Math.pow(26, al-i-1);
+    };
+    // console.log(a, numout-1);
+    if(numout==0){
+        return NaN;
     }
-
+    return numout-1;
-    return ret;
 };
 
 //列下标  数字转字母
-function chatatABC(index) {
+function chatatABC(n) {
-    let wordlen = columeHeader_word.length;
+    // let wordlen = columeHeader_word.length;
 
-    if (index < wordlen) {
+    // if (index < wordlen) {
-        return columeHeader_word[index];
+    //     return columeHeader_word[index];
-    }
+    // }
-    else {
+    // else {
-        let last = 0, pre = 0, ret = "";
+    //     let last = 0, pre = 0, ret = "";
-        let i = 1, n = 0;
+    //     let i = 1, n = 0;
 
-        while (index >= (wordlen / (wordlen - 1)) * (Math.pow(wordlen, i++) - 1)) {
+    //     while (index >= (wordlen / (wordlen - 1)) * (Math.pow(wordlen, i++) - 1)) {
-            n = i;
+    //         n = i;
-        }
+    //     }
 
-        let index_ab = index - (wordlen / (wordlen - 1)) * (Math.pow(wordlen, n - 1) - 1);//970
+    //     let index_ab = index - (wordlen / (wordlen - 1)) * (Math.pow(wordlen, n - 1) - 1);//970
-        last = index_ab + 1;
+    //     last = index_ab + 1;
 
-        for (let x = n; x > 0; x--) {
+    //     for (let x = n; x > 0; x--) {
-            let last1 = last, x1 = x;//-702=268, 3
+    //         let last1 = last, x1 = x;//-702=268, 3
 
-            if (x == 1) {
+    //         if (x == 1) {
-                last1 = last1 % wordlen;
+    //             last1 = last1 % wordlen;
 
-                if (last1 == 0) {
+    //             if (last1 == 0) {
-                    last1 = 26;
+    //                 last1 = 26;
-                }
+    //             }
 
-                return ret + columeHeader_word[last1 - 1];
+    //             return ret + columeHeader_word[last1 - 1];
-            }
+    //         }
 
-            last1 = Math.ceil(last1 / Math.pow(wordlen, x - 1));
+    //         last1 = Math.ceil(last1 / Math.pow(wordlen, x - 1));
-            //last1 = last1 % wordlen;
+    //         //last1 = last1 % wordlen;
-            ret += columeHeader_word[last1 - 1];
+    //         ret += columeHeader_word[last1 - 1];
+
+    //         if (x > 1) {
+    //             last = last - (last1 - 1) * wordlen;
+    //         }
+    //     }
+    // }
+
+    var orda = 'a'.charCodeAt(0); 
+   
+    var ordz = 'z'.charCodeAt(0); 
+   
+    var len = ordz - orda + 1; 
+   
+    var s = ""; 
+   
+    while( n >= 0 ) { 
+   
+        s = String.fromCharCode(n % len + orda) + s; 
+   
+        n = Math.floor(n / len) - 1; 
    
-            if (x > 1) {
-                last = last - (last1 - 1) * wordlen;
-            }
-        }
     } 
+   
+    return s.toUpperCase(); 
 };
 
 function ceateABC(index) {