1. 首页
  2. 问答
  3. 从下拉菜单输出差异时获取空值？ （Javascript）

从下拉菜单输出差异时获取空值？ （Javascript）

2017-04-15 135 views
2

我在寻找建立一个简单的营养计算器，将一种食物和另一种食物之间的差异，然后输出营养成分的差异。有两件事情我无法搞清楚：从下拉菜单输出差异时获取空值？ （Javascript）

  1. 的代码看起来工作正常，但是当我增加它返回NaN值，有时只是计算它为0
  2. 的代码量是唯一能使用第一个文本框来链接值（两个食品都使用第一个文本框中的值，所以第二个文本框中的值不会做任何改变），我还没有弄清楚如何计算单位之间的差异在第一个文本框和另一个文本框中的单位。我是否必须为第二个食品创建相同的功能？

代码我到目前为止有：

var stocks = [ 
 
    ["Beef (80/20) raw","oz",115.4451262,2.094125,1.199617347,72,4.85,5.65,0,2.142,19,20,0.0001275510204,0.375,0.75,22.15988372,0.3768292943,4 ], 
 
    ["Beef (90/10) raw","oz",115.4451262,2.094125,1.199617347,50,5.65,2.83,0,1.109,19,18,0.0001275510204,0.375,0.75,22.15988372,0.3768292943,4 ], 
 
    ["Chicken breast","oz",32.39053977,0.320375,0.07197704082,34,6.38,0.74,0,0.16,13,21,0.01631172356,0.10625,0.2125,3.149953226,0.3765300698,4 ], 
 
    ["Chicken thighs/legs","oz",32.39053977,0.320375,0.07197704082,125,2.72,12.54,0,3.431,14,30,0.01631172356,0.10625,0.2125,3.149953226,0.3765799405,4 ], 
 
    ["Milk (whole)","fl oz",7.638924987,0.146025,0.0002099330357,19,0.96,0.99,1.54,0.569,13,0.000000357142857142857,0.099609375,0.19921875,1.228661955,0.2415694159,8 ], 
 
    ["Milk (2%)","fl oz",7.638924987,0.06112164455,0.0002099330357,15,1.06,0.58,1.54,0.363,16,2,0.000000357142857142857,0.099609375,0.19921875,1.228661955,0.2417190282,8 ], 
 
    ["Pizza (cheese)","slice",42,0.9700347449,0.006297991071,285,12.19,10.37,3.83,4.778,640,18,0.00001071428571,2.98828125,5.9765625,36.85985865,0.466697922,4 ], 
 
    ["Ice Cream","cup",32.59312,0.6168324833,0.002345956329,274.71344,4.6095984,14.4806576,27.9835216,8.94913952,107.09168,55.87392,0.000003990994286,1.11311325,2.2262265,13.73003196,2.889031735,1 ], 
 
    ["Milk (skim)","fl oz",7.638924987,0.05927058824,0.0002099330357,10,1.03,0.02,1.54,0.017,13,1,0.000000357142857142857,0.099609375,0.19921875,1.228661955,0.2415694159,8 ], 
 
    ["Eggs (large)","each",43.13341461,0.514206,0.007354326122,78,6.29,5.3,0.2,1.633,62,186,0.001666666667,0.265625,0.53125,3.713549,0.1305756192,1 ], 
 
    ["Lamb","oz",78.125,2.8105,1.199617347,80,4.69,6.64,0,2.889,17,21,0.03333333333,0.3125,0.625,2.274815967,0.3767295528,4 ], 
 
    ["Cheese (hard)","slice (oz)",37.44571072,1.35025,0.002099330357,105,6.59,8.41,0.14,5.32,159,27,0.000003571428571,0.99609375,1.9921875,12.28661955,0.1303337926,1 ], 
 
    ["Yogurt","oz",5.833333333,0.09375,0.0002099330357,17,0.98,0.92,1.32,0.595,13,4,0.000000357142857142857,0.099609375,0.19921875,1.228661955,0.2229453548,6 ], 
 
    ["Greek yogurt, vanilla (nonfat)","fl oz",15,0.08232711306,0.0005248325893,22,2.45,0.05,1.01,0.038,10,1,0.000000892857142857143,0.3984375,0.796875,3.071654888,0.1965527472,6 ], 
 
    ["Chocolate","oz",127.316,0.1862906,0.00004198660714,151,2.16,8.39,14.57,5.238,22,7,0.0000000714285714285714,0.019921875,0.03984375,1.601963425,1.345070603,1.45 ], 
 
    ["Cacao","oz",179.739,0.625,0,136,1.19,8.51,15.45,5.032,3,0,0,0,0,3.390577585,1.418619303,1.45 ], 
 
    ["Salmon (farmed)","oz",0.498125,0.56925,0,59,5.79,3.8,0,0.864,17,16,0.004464285714,0.078125,0.15625,0.5593288054,0.3767295528,4 ], 
 
    ["Tuna (canned in oil)","oz",0.498125,0.1197485281,0,56,8.26,2.33,0,0.435,118,5,0.000270197828,1.0625,2.125,0.5593288054,0.3817664985,4 ], 
 
    ["Mayo","oz",14.41309121,0.121875,0.001838581531,193,0.27,21.22,0.16,3.318,180,12,0.0004166666667,0.06640625,0.1328125,0.92838725,0.1330741748,0.5 ], 
 
    ["Pulled Pork raw","oz",44.84498316,0.63525,0.1411314526,53,4.94,3.5,0,1.232,17,18,0.0005208333333,0.21875,0.4375,1.592371177,0.3767295528,4 ], 
 
    ["Butter (salted)","oz",41.58720633,0.5875,0.00440859375,203,0.24,22.95,0.02,14.537,182,61,0.0000075,2.091796875,4.18359375,25.80190106,0.121322241,1 ], 
 
    ["Soy Burger","oz",21.8,0.048125,0,50,4.44,1.78,0.3,0.408,161,1,0,0,0,2.314125,0.03342563782,4 ], 
 
    ["Vegan Nuggets (soy)","oz",21.8,0.048125,0,52,4.88,1.63,0.65,0.325,172,0,0,0,0,2.314125,0.06360340429,4 ], 
 
    ["Soymilk (original)","fl oz",2.319532348,0.02445449777,0,17,1,0.54,1.21,0.063,16,0,0,0,0,1.168382863,0.1032302684,8 ], 
 
    ["Tofu","oz",25.25,0.09625,0,23,2.82,1.49,0.2,0.26,1,0,0,0,0,4.62825,0.01698083545,4 ], 
 
    ["Tempeh","oz",12.383064,0.0230998152,0,54,5.74,3.06,0,0.719,3,0,0,0,0,1.110771114,0.0001496122504,4 ], 
 
    ["Mixed Nuts","oz",18.72285536,0.18425,0,172,5.53,15.17,1.42,2.271,1,1,0,0,0,1.019662873,0.1202597201,1 ], 
 
    ["Bread","slice",9.735884788,0.1530147137,0,79,3.09,1.31,1.66,0.202,137,0,0,0,0,0.5625,0.1473592997,2 ], 
 
    ["Lentils","oz",30.3684714,0.07425,0,33,2.55,0.11,0.51,0.015,1,0,0,0,0,2.287814892,0.04322383072,7.1 ], 
 
    ["Black Beans","oz",30.3684714,0.141625,0,37,2.31,0.1,0.09,0.025,1,0,0,0,0,1.555714169,0.007668804863,7.1 ], 
 
    ["Tomato Sauce","oz",3.13704,0.09375,0,11,0.47,0.06,1.37,0.008,57,0,0,0,0,0.4188459746,0.1188197409,8 ], 
 
    ["Pinto Beans","oz",30.3684714,0.141625,0,40,2.55,0.18,0.09,0.038,0,0,0,0,0,0.9075003086,0.007618934113,7.1 ], 
 
    ["French Fries","oz",2.9337142,0.0417335921,0,56,0.82,1.91,0.14,0.359,113,0,0,0,0,0.4200133922,0.01748707005,4 ], 
 
    ["Peanut Butter","oz",36,0.2145,0,167,6.81,14.13,2.97,2.153,138,0,0,0,0,3.675378676,0.2583069893,1 ], 
 
    ["Olive Oil","oz",21.77842536,0.2306145384,0,250,0,28.3,0,3.908,1,0,0,0,0,1.512500057,0.00004987075014,0.5 ], 
 
    ["Banana","1 medium",6.440662244,0.1763699536,0,105,1.29,0.39,14.43,0.132,1,0,0,0,0,0.1768995697,1.221618974,1 ], 
 
    ["Mixed vegetables","oz",2.41150377,0.125,0,18,0.81,0.04,0,0.009,10,0,0,0,0,3,0.0004987075014,4 ], 
 
    ["Nutritional Yeast","g",0.08506329224,0.00706361088,0,3.9859577,0.5989518739,0,0,0,0,0,0,0,0,0,0,5 ], 
 
    ["Rice (white)","oz",25.46308329,0.34375,0,102,1.87,0.16,0,0.045,0,0,0,0,0,0.3995205753,0,2 ], 
 
    ["Potatoes","oz",1.872285536,0.03575,0,16,0.73,0.03,0.2,0.007,3,0,0,0,0,0.06927480776,0.01708057695,5.3 ], 
 
    ["Vegetable Oil","oz",17.70433203,0.125,0,205,0,23.8,0,19.937,0,0,0,0,0,5.300817694,0,0.5 ], 
 
    ["Wheat (flour)","1/4 cup",10.11034189,0.03087703323,0,102,3.39,0.47,0.09,0.069,1,0,0,0,0,0.3995205753,0.007668804863,1 ], 
 
    ["Margarine","oz",9.915624199,0.06125,0,102,0.28,11.32,0,2.048,222,0,0,0,0,5.300817694,0.01107130653,1 ], 
 
    ["Corn Syrup","fl oz",11.15931776,0.01728062914,0,109,0,0,29.31,0,1,0,0,0,0,0.4854914297,2.481282747,1 ], 
 
    ["Sugar","oz",11.23371322,0.01503093504,0,110,0,0,28.3,0,0,0,0,0,0,0.4340729937,2.395731504,1 ], 
 
    ["Corn (grain)","oz",6.74022793,0.0104375,0,103,2.67,1.34,0.18,0.189,10,0,0,0,0,0.4549631935,0.01573657573,1 ], 
 
    ["Soda","fl oz",10.64647779,0.02494335117,0,13,0,0.08,3.05,0,1,0,0,0,0,0.1939638153,0.2582470824,12 ] 
 
] 
 

 
function Stock (data) { 
 
    return { 
 
    name: data[0], 
 
    servingUnit: data[1], 
 
    calories: [data[5], ''], 
 
    protein: [data[6], 'g'], 
 
    fat: [data[7], 'g'], 
 
    saturatedFat: [data[8], 'g'], 
 
    sugar: [data[9], 'g'], 
 
    sodium: [data[10], 'mg'], 
 
    cholesterol: [data[11], 'mg'] 
 
    } 
 
} 
 

 
stocks = stocks.map(Stock) 
 

 
var $selects = $('.selectStock') 
 
var $quantity = $('#numberOfStocks') 
 
var $comparisonResult = $('.comparison .result') 
 

 
$selects.each(function() { 
 
    $(this).append(stocks.map(function(stock, i) { 
 
    return new Option(stock.name, i) 
 
    })) 
 
}) 
 

 
function format(data, multiplier, digits) { 
 
    data[0] = (+(data[0] * multiplier).toFixed(digits)).toLocaleString() 
 
    return data.join(' ') 
 
} 
 

 
function stockFacts(stock, quantity) { 
 
    return [ 
 
    format(stock.calories, quantity, 2) + ' calories<br>' + 
 
    format(stock.protein, quantity, 2) + ' of protein<br>' + 
 
    format(stock.fat, quantity, 3) + ' of fat<br>' + 
 
    format(stock.saturatedFat, quantity, 2) + ' of saturated fat<br>' + 
 
    format(stock.sugar, quantity, 2) + ' of sugar<br>' + 
 
    format(stock.sodium, quantity, 2) + ' of sodium<br>' + 
 
    format(stock.cholesterol, quantity, 2) + ' of cholesterol<br>' 
 
    ] 
 
} 
 

 
$selects.add($quantity).on('input', updateAmount) 
 

 
function getStock (select) { 
 
    return stocks[+select.value] 
 
} 
 

 
function updateAmount() { 
 
    var quantity = +$quantity.val() 
 
    
 
    // Not sure what this line was supposed to do 
 
    if (quantity < 0) quantity = stock[17] 
 
    
 
    $selects.each(function() { 
 
    var $result = $(this).nextAll('.result').empty() 
 
    var $amount = $(this).prev().find('.servingUnit').empty() 
 
    var stock = getStock(this) 
 
    if (!stock) return 
 
    
 
    $amount.text(' (' + quantity + ' ' + stock.servingUnit + ')') 
 
    
 
    $result.html(stockFacts(stock, quantity)) 
 
    }) 
 
    
 
    var selectedStocks = [].map.call($selects, getStock) 
 
    $comparisonResult.empty() 
 
    if (!selectedStocks[0] || !selectedStocks[1]) return 
 
    var diff = {} 
 
    Object.keys(selectedStocks[0]).forEach(function (k) { 
 
    if (/^(name|servingUnit)$/.test(k)) return 
 
    var first = selectedStocks[0][k] 
 
    var second = selectedStocks[1][k] 
 
    diff[k] = [Math.abs(first[0] - second[0]), first[1], first > second ? 'more' : 'less'] 
 
    }) 
 
    $comparisonResult.html(stockFacts(diff, quantity)) 
 
}
.side { 
 
    float:left; 
 
    margin: 0.5%; 
 
    width: 33%; 
 
    
 
} 
 
.sideone { 
 
    float:middle; 
 
    margin: 0.5%; 
 
    width: 33%; 
 
    position:relative; 
 
    clear:both; 
 
} 
 
.mid { 
 
    float:middle; 
 
    margin: 0.5%; 
 
    width: 33%; 
 
} 
 
.comparison { 
 
    float:right; 
 
    width:66%; 
 
    position:relative; 
 
    display: inline-block; 
 
}
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script> 
 

 
<head> 
 
    <meta name="viewport" content="width=10px, initial-scale=1.0"> 
 
</head> 
 

 
<body> 
 
    <label> 
 
    <div class = "side"> 
 
    Amount: 
 
    <input type="number" id="numberOfStocks" value="1" min="0" /> 
 
    </div> 
 
    <br> 
 
    <br> 
 
    <br> 
 
    <br> 
 
    </label> 
 

 
    <div> 
 
    <div class="sideone"> 
 
     <h2>First Item<span class="servingUnit"></span>:</h2> 
 
     <select class="selectStock"> 
 
     <option value="-1">Pick a food!</option> 
 
     </select> 
 
    </div> 
 
    <label> 
 
    <div class = "side"> 
 
     Amount: 
 
    <input type="number" id="numberOfStocks" value="1" min="0" /> 
 
    </div> 
 
    <br> 
 
    <br> 
 
    <br> 
 
    <br> 
 
    </label> 
 
    <div class="sideone"> 
 
     <h2>Second Item<span class="servingUnit"></span>:</h2> 
 
     <select class="selectStock"> 
 
     <option value="-1">Pick a food!</option> 
 
     </select> 
 
     <br> 
 
     <br> 
 
    </div> 
 
    <div class="comparison side"> 
 
     <h2>Comparison:</h2> 
 
     <br> 
 
     <br> 
 
     <div class="result"></div> 
 
    </div> 
 
    </div> 
 
</body>

真的很感谢这个帮助/指导。谢谢一堆！

来源

2017-04-15 Dick Thompson

回答

2

敬请收看普拉克：https://plnkr.co/edit/AwaiAKQYJHlbvzvRYDqi

全面披露

  • 我试着不要太多改变你的代码，并且只固定两个提到的问题。
  • 如果我可以添加，而不太了解代码。
  • 如果计算有问题，我没有修正，也没有尝试去理解它们。

的问题的答案：

  1. 我增加了一个功能，从后来被它float parseToFloatWithoutCommas(str)计算格式的数字删除逗号。

  2. 我换了两个文本框ID's到class，就像你与select盒，因为你不能使用相同的ID更多，一旦在HTML，但class可以:)

享受;-)

来源

2017-04-16 11:05:33 EfiBN

+0

汤普森先生，记得接受答案，如果它帮助你，谢谢;-) – EfiBN

相关问题

 相关问题