Javascript forEach 循環

Question

試圖使這個功能成為現實。 我認為問題出在我的 for 循環中。

function forEach(array, callback){    
    console.log(array, callback);
    for(var i = 0; i < array.length; i++) {

    }
}

 // testing your code with console.assert
var total = 1;
var myArray = [1, 2, 3, 4];
function multiplyTotal(a) {
    total *= a;
}
forEach(myArray, multiplyTotal);
// and finally assert; if this fails, the program stops
console.assert(total === 24);

Answer 1

function forEach(array, callback){    
    console.log(array, callback);
    for(var i = 0; i < array.length; i++) {
       callback(array[i]); // you need to call callback function
    }
}

Answer 2

此外，Javascript 已經為此提供了一個內置函數：

myArray.forEach(multiplyTotal);

http://www.w3schools.com/jsref/jsref_forEach.asp