当我把js逻辑写在闭包中作为一个单独的js文件时,一切都很好,如下:
(function(win){
//main logic here
win.expose1 = ....
win.expose2 = ....
})(window)
但是当我尝试在同一个js文件中的闭包之前插入一个日志替代函数时,
window.Glog = function(msg){
console.log(msg)
}
// this was added before the main closure.
(function(win){
//the former closure that contains the main javascript logic;
})(window)
它抱怨有一个TypeError:
Uncaught TypeError: (intermediate value)(...) is not a function
我做错了什么?
**Error Case:**
var handler = function(parameters) {
console.log(parameters);
}
(function() { //IIFE
// some code
})();
输出:TypeError:(中间值)(中间值)不是函数
*如何修复IT ->,因为你缺少半冒号(;)分开的表达式;
**Fixed**
var handler = function(parameters) {
console.log(parameters);
}; // <--- Add this semicolon(if you miss that semi colan ..
//error will occurs )
(function() { //IIFE
// some code
})();
为什么会出现这个错误?
原因:
ES6标准中给出的自动分号插入的特定规则
该错误是由于第三行缺少分号造成的:
window.Glog = function(msg) {
console.log(msg);
}; // <--- Add this semicolon
(function(win) {
// ...
})(window);
ECMAScript规范对自动插入分号有特定的规则,但是在这种情况下,分号不会自动插入,因为下一行开始的括号表达式可以被解释为函数调用的参数列表。
这意味着没有分号,匿名窗口。Glog函数被调用时使用一个函数作为msg参数,后面跟着(window),它随后试图调用返回的任何东西。
下面是代码的解释:
window.Glog = function(msg) {
console.log(msg);
}(function(win) {
// ...
})(window);
错误案例:
var userListQuery = {
userId: {
$in: result
},
"isCameraAdded": true
}
( cameraInfo.findtext != "" ) ? searchQuery : userListQuery;
输出:
TypeError: (intermediate value)(intermediate value) is not a function
修正:你缺少一个分号(;)分隔表达式
userListQuery = {
userId: {
$in: result
},
"isCameraAdded": true
}; // Without a semi colon, the error is produced
( cameraInfo.findtext != "" ) ? searchQuery : userListQuery;