通过断点而不是多个 else if 语句查找索引

Question

我正在尝试根据人的身高生成尺寸。目前我的程序可以工作，但我想找到一种更短的方法来获取大小，而不是使用所有这些else if语句。我想循环通过“断点”来找到相应的索引。这是我的原始代码+我的想法。const sizes = ['xxs', 'xxs or xs', 'xs', 'xs or s'] // Goes on for all sizes...function generateSize(height) {    let size;    if (height < 142) {        size = sizes[0];    } else if (height >= 142 && height < 148) {        size = sizes[1];    } else if (height >= 148 && height < 154) {        size = sizes[2];    } else if (height >= 154 && height < 160) {        size = sizes[3]; // Goes on for all sizes...    } else {        size = 'larger...';    }    return size;}// Example of what I had in mind.const heightBreakpoints = [142, 148, 154, 160];function getByBreakpoints(breakpoints, height){ // Part where I am stuck.    let index;    // Loop through breakpoints...    return index;}const sizeIndex = (getByBreakpoints(heightBreakpoints, 158));const s = sizes[sizeIndex];

Answer 1

 const sizes = ['xxs', 'xxs or xs', 'xs', 'xs or s', "even another one here"]

// Goes on for all sizes...

function generateSize(height){

    let size;

    let left = 142;

    let right = 142;

    // Initialize the variables for comparison

    // Left and right comparison based on position of "&"

    // This is just user-defined

    for(var i = 0; i < sizes.length; i++){

        if(height < right){

          size = sizes[i];

          return size;

        }

        else {

            // add counter from here

            // This takes us to the next item in the array

            i += 1;

            // add right comparison with intervals of 6

            right += 6;

            if(height >= left && height < right){

                size = sizes[i];

                return size;

            }

            else {

              // add left comparison with intervals of 6

              left += 6;

              // revert the counter to its initial value

              i -= 1;

            }

        }

    }

}

console.log("First: " + generateSize(141))

console.log("Second: " + generateSize(147))

console.log("Third: " + generateSize(153))

console.log("Fourth: " + generateSize(159))

console.log("Last: " + generateSize(161));

// Note this 161, which will return the new last value in the array

这假设您的大小间隔为 6，（它们是）并返回与数组对应的相应值

Answer 2

我认为你可以通过调整你的起始数据结构来大大简化这一点。如果我们有一个将大小及其断点联系在一起的对象数组怎么办：

const sizeMap = [

    { maxHeight: 142, size: 'xxs' },

    { maxHeight: 148, size: 'xxs or xs' },

    { maxHeight: 154, size: 'xs' },

    { maxHeight: 160, size: 'xs or s' },

]

const getSize = height => sizeMap.find(item => height < item.maxHeight).size

console.log(getSize(143))

数组函数find返回满足您条件的第一个值。这种方法工作的先决条件是让您的数组对象的高度按升序排列。

Answer 3

if(height<160){

height-=142;

if(height<0){size=sizes[0]}

else{

size=sizes[(hieght)%6]

}

}

else{

size='larger...'

}

检查这是否适用于所有情况我困了