Javascript 将变量传递给 foreach 函数
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pass a variable to foreach function
提问by Christoph
Hi I want pass antwoordto
嗨，我想传递antwoord给
opleidingArray.forEach(haalScoresOp, antwoord);
opleidingArray.forEach(haalScoresOp, antwoord);
So I can use it in the
所以我可以在
HaalScoresOp
HaalScoresOp
function. I cannot get this to work. I also tried binding but this does not function.
功能。我不能让它工作。我也试过绑定，但这不起作用。
I am getting antwoord is not defined as an error.
我得到 antwoord 未定义为错误。
var antwoordenPerVraag = [2,1,3];
console.log(VragenEnScores.vragen[0].opleidingen[0]);
antwoordenPerVraag.forEach(berekenEindresultaten);
function berekenEindresultaten(item, index) {
var opleidingArray = VragenEnScores.vragen[index].opleidingen;
var antwoord = "bla";
opleidingArray.forEach(haalScoresOp, antwoord);
// score nog doorgeven aan haalscores op = het item
}
function haalScoresOp(item, index) {
console.log("haal score op voor");
console.log(item.naam);
console.log(item.scores);
console.log("haal antwoord op");
console.log(antwoord);
}
回答by deceze
The way you're referencing antwoordinside haalScoresOpis invalid/nonsense/not good. You're referencing it as if it was a variable in scope… well, it's not. The function should accept it as parameter just like its other parameters:
您在antwoord内部引用的方式haalScoresOp无效/无意义/不好。你引用它就好像它是一个范围内的变量......好吧，它不是。该函数应该像其他参数一样接受它作为参数：
function haalScoresOp(antwoord, item, index) {
..
console.log(antwoord);
}
Then you can pass it in on the caller's side:
然后你可以在调用者端传递它：
opleidingArray.forEach(function (item, index) {
haalScoresOp(antwoord, item, index)
});
or:
或者：
opleidingArray.forEach(haalScoresOp.bind(null, antwoord));
回答by user12387426
You can simply use :
您可以简单地使用：
opleidingArray.forEach(haalScoresOp, antwoord);
And refer to antwoord inside the haalScoresOp function as follow:
并在 haalScoresOp 函数中引用 antwoord 如下：
function haalScoresOp(){
var diantwoord = this.valueOf();
}
antwoord is passed as 'this' object to the function regarding the type
antwoord 作为“this”对象传递给关于类型的函数
回答by kurdtpage
You could change the haalScoresOpfunction to be an anonymous function inside the berekenEindresultatenfunction:
您可以将haalScoresOp函数更改为函数内的匿名berekenEindresultaten函数：
var antwoordenPerVraag = [2,1,3];
console.log(VragenEnScores.vragen[0].opleidingen[0]);
antwoordenPerVraag.forEach(berekenEindresultaten);
function berekenEindresultaten(item, index) {
var opleidingArray = VragenEnScores.vragen[index].opleidingen;
var antwoord = "bla";
opleidingArray.forEach(function(item, index){
// score nog doorgeven aan haalscores op = het item
console.log("haal score op voor");
console.log(item.naam);
console.log(item.scores);
console.log("haal antwoord op");
console.log(antwoord);
});
}
This would keep the scope of the antwoordvariable inside the berekenEindresultatenfunction
这将使antwoord变量的范围保持在berekenEindresultaten函数内
