本文介绍了TypeError:无法读取未定义Javascript的属性'forEach'的处理方法,对大家解决问题具有一定的参考价值,需要的朋友们下面随着小编来一起学习吧!
问题描述
以下是我正在获取无法读取未定义的属性'forEach'
的代码.
Following is the code in which I am getting Cannot read property 'forEach' of undefined
.
const print2 = function(x, y) {
console.log(x*y)
}
[1,2,3,4].forEach( x => print2(x, 20) )
让我知道我在这里做错了,尽管我愿意-
Let me know what I am doing wrong here, though if I do -
function print2(x, y) {
console.log(x*y)
}
[1,2,3,4].forEach( x => print2(x, 20) )
这很好.
推荐答案
由于该函数后没有分号,因此该代码段的解释如下:
Since there's no semicolon after the function, the snippet gets interpreted as the following:
const print2 = function(x, y) {
console.log(x*y)
}[1,2,3,4].forEach( x => print2(x, 20) )
这意味着它正在尝试索引该函数.在函数之后或数组文字之前添加分号:
Which means that it's trying to index into the function. Add a semicolon either after the function, or before the array literal:
const print2 = function(x, y) {
console.log(x*y)
};
[1,2,3,4].forEach( x => print2(x, 20) )
或
const print2 = function(x, y) {
console.log(x*y)
}
;[1,2,3,4].forEach( x => print2(x, 20) )
此处提供有关Javascript自动分号插入的更多信息: JavaScript自动分号插入(ASI)的规则是什么?
More about Javascript's automatic semicolon insertion here: What are the rules for JavaScript's automatic semicolon insertion (ASI)?
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