JavaScript:使用 Array 方法编写多个函数

Question

我需要帮助将多个重复的函数写入一个传递变量的函数，而不是一遍又一遍地编写。

目前，我有一些 JavaScript 函数可以做同样的事情，只是使用不同的变量和字符串。

var Apple_Data = Info.Apple; // grabs string objects from JSON file
var Banana_Data = Info.Banana; // grabs string objects from JSON file
function CompareApple() {

                if (counter == 0) {
                    prev_Apple_Data = Apple_Data;

                }

                if (Apple_Data > prev_Apple_Data) {
                    if ((Math.abs(Apple_Data - prev_Apple_Data) >= prev_Apple_Data / 2))
                        document.getElementById("Apple_img").src = "img/yelow.png",
                    StartCnt(1);
                    else if ((Math.abs(Apple_Data - prev_Apple_Data) <= prev_Apple_Data / 2))
                        document.getElementById("Apple_img").src = "img/green.png";

                }

                else if (Apple_Data < prev_Apple_Data) {
                    if ((Math.abs(Apple_Data - prev_Apple_Data) >= prev_Apple_Data / 2))
                        document.getElementById("Apple_img").src = "img/yelow.png",
                    StartCnt(1);
                    else if ((Math.abs(Apple_Data - prev_Apple_Data) <= prev_Apple_Data / 2))
                        document.getElementById("Apple_img").src = "img/green.png";
                }

                prev_Apple_Data = Apple_Data;
}

function CompareBanana() {

                if (counter == 0) {
                    prev_Banana_Data = Banana_Data;

                }

                if (Banana_Data > prev_Banana_Data) {
                    if ((Math.abs(Banana_Data - prev_Banana_Data) >= prev_Banana_Data / 2))
                        document.getElementById("Banana_img").src = "img/yelow.png",
                    StartCnt(1);
                    else if ((Math.abs(Banana_Data - prev_Banana_Data) <= prev_Banana_Data / 2))
                        document.getElementById("Banana_img").src = "img/green.png";

                }

                else if (Banana_Data < prev_Banana_Data) {
                    if ((Math.abs(Banana_Data - prev_Banana_Data) >= prev_Banana_Data / 2))
                        document.getElementById("Banana_img").src = "img/yelow.png",
                    StartCnt(1);
                    else if ((Math.abs(Banana_Data - prev_Banana_Data) <= prev_Banana_Data / 2))
                        document.getElementById("Banana_img").src = "img/green.png";
                }

                prev_Banana_Data = Banana_Data;
}

如果我想将这些写在 1 个传递变量的函数中，我该怎么做？我在想这个过程会是这样的，必须制作 4 个不同的空数组

Var PreviousData = []; 
Var CurrentData = [];
Var DeclaredData = []; 
Var ImageArray = []; 

然后写一个函数传入这些数组

function Compare(PreviousData, CurrentData, DeclaredData, ImageArray){ 
    if (counter ==0){
        PreviousData = DeclaredData; 
    }
    if (Declared_Data > PreviousData) {
                    if ((Math.abs(Declared_Data - PreviousData) >= PreviousData / 2))
                        document.getElementById("ImageArray").src = "img/yellow.png",
                    StartCnt(1);
                    else if ((Math.abs(Declared_Data - PreviousData) <= PreviousData / 2))
                        document.getElementById("ImageArray").src = "img/green.png";

                }

                else if (Declared_Data < PreviousData) {
                    if ((Math.abs(Declared_Data - PreviousData) >= PreviousData / 2))
                        document.getElementById("ImageArray").src = "img/yellow.png",
                    StartCnt(1);
                    else if ((Math.abs(Declared_Data - PreviousData) <= PreviousData / 2))
                        document.getElementById("ImageArray").src = "img/green.png";
                }
}

计数器和 Math.abs 被写在那里以循环遍历对象并且当前有效。

然后通过类似的方式初始化函数

Compare(previousData, info.Apple, DeclaredData, ImageArray);

Answer 1

您可以将代码简化为:

var infoUpd = {
   'prev': false
};

for (key in Info) {
    infoUpd[ key ] = {
        'data': Info[ key ],
        'img': document.getElementById(key+"_img")
    }
}


function compareStuff( key ) {
        var stuffData = infoUpd[ key ];
    if ( infoUpd.prev ) {
        var calcResult = Math.abs(stuffData.data - infoUpd.prev) >= (infoUpd.prev / 2);
        if (stuffData.data !== infoUpd.prev) {
            if ( calcResult ) {
                stuffData.img.src = "img/yelow.png";
            } else {
                stuffData.img.src = "img/green.png";
            }
        }
    }
    infoUpd.prev = stuffData.data; 
}

compareStuff( 'Apple' );
compareStuff( 'Banana' );