获取 JavaScript 中数组对象的匹配范围项

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英文:

Get matched range item from array of objects javascript

问题

I can provide the translation for the code portion:

  1. let tiers = [
  2.    {id: 1, discount_percent: 0, quantity: 6, title: "Tier 1"},
  3.    {id: 2, discount_percent: 5, quantity: 8, title: "Tier 2"},
  4.    {id: 3, discount_percent: 10, quantity: 10, title: "Tier 3"},
  5.    {id: 4, discount_percent: 12, quantity: 12, title: "Tier 4"},
  6.    {id: 5, discount_percent: 14, quantity: 14, title: "Tier 5"},
  7.    {id: 6, discount_percent: 20, quantity: 16, title: "Tier 6"},
  8.    {id: 7, discount_percent: 40, quantity: 18, title: "Tier 7"},
  9.    {id: 8, discount_percent: 50, quantity: 50, title: "Tier 8"},
  10. ]
  12. function calculateDiscount() {
  13.    const ordersQuanity = 10;
  14.    const tier = tiers.find((_tier) => _tier.quantity <= ordersQuanity);
  15.    // Rest of your code...
  16. }

Please note that I have corrected the code by removing HTML escape codes from the title properties to make it more readable.

英文:

I have one array which is named as tiers and one quantity variable. Now I am trying to get the matched range value from my tier array. Based on the matched result I want to calculate the discount. I tried to with find method but it gives me an unexpected ouput.

Actual output
{id: 1, discount_percent:0, quantity:6, title:&quot;Tier 1&quot;}

Expeceted Output
{id: 3, discount_percent:10, quantity:10, title:&quot;Tier 3&quot;}

  1. let tiers = [
  2.    {id: 1, discount_percent:0, quantity:6, title:&quot;Tier 1&quot;},
  3.    {id: 2, discount_percent:5, quantity:8, title:&quot;Tier 2&quot;},
  4.    {id: 3, discount_percent:10, quantity:10, title:&quot;Tier 3&quot;},
  5.    {id: 4, discount_percent:12, quantity:12, title:&quot;Tier 4&quot;},
  6.    {id: 5, discount_percent:14, quantity:14, title:&quot;Tier 5&quot;},
  7.    {id: 6, discount_percent:20, quantity:16, title:&quot;Tier 6&quot;},
  8.    {id: 7, discount_percent:40, quantity:18, title:&quot;Tier 7&quot;},
  9.    {id: 8, discount_percent:50, quantity:50, title:&quot;Tier 8&quot;},
  10. ]
  1. function calculateDiscount(){
  2.    const ordersQuanity = 10;
  3.    const tier = tiers.find((_tier) =&gt; _tier.quantity &lt;= ordersQuanity);
  4.    ...
  5. }

答案1

得分: 1

对于具有discount_percent和quantity的多个对象的一般情况，.find不是正确的方法，因为它会在找到匹配项时停止。考虑使用.reduce - 如果正在迭代的元素通过测试并且它的discount_percent大于累加器中的当前元素（如果累加器中有任何内容），则返回它。

  1. let tiers = [
  2.    {id: 1, discount_percent:0, quantity:6, title:"Tier 1"},
  3.    {id: 2, discount_percent:5, quantity:8, title:"Tier 2"},
  4.    {id: 3, discount_percent:10, quantity:10, title:"Tier 3"},
  5.    {id: 4, discount_percent:12, quantity:12, title:"Tier 4"},
  6. ]
  7. function calculateDiscount(){
  8.    const ordersQuanity = 10;
  9.    const bestTier = tiers.reduce((a, tier) => (
  10.      tier.quantity <= ordersQuanity && (!a || tier.discount_percent > a.discount_percent)
  11.        ? tier
  12.        : a
  13.    ), null) || tiers[0]; // alternate with the first element of the array
  14.    // if you want to default to that tier even if the quantity isn't sufficient
  15.    console.log(bestTier);
  16. }
  17. calculateDiscount();

如果你假设每次增加的discount_percent都伴随着更大的数量，并且数组已排序，你可以使用.find，如果首先反转数组（以便首先迭代具有最大discount_percent的项目）。

  1. let tiers = [
  2.    {id: 1, discount_percent:0, quantity:6, title:"Tier 1"},
  3.    {id: 2, discount_percent:5, quantity:8, title:"Tier 2"},
  4.    {id: 3, discount_percent:10, quantity:10, title:"Tier 3"},
  5.    {id: 4, discount_percent:12, quantity:12, title:"Tier 4"},
  6. ];
  7. const tiersReversed = [...tiers].reverse();
  8. function calculateDiscount(){
  9.    const ordersQuanity = 10;
  10.    const tier = tiersReversed
  11.      .find((_tier) => _tier.quantity <= ordersQuanity)
  12.       || tiers[0]; // alternate with the first element of the array
  13.    // if you want to default to that tier even if the quantity isn't sufficient
  14.    console.log(tier);
  15. }
  16. calculateDiscount();

这段代码对于编辑后的问题中的数据集同样有效。

  1. let tiers = [
  2.    {id: 1, discount_percent:0, quantity:6, title:"Tier 1"},
  3.    {id: 2, discount_percent:5, quantity:8, title:"Tier 2"},
  4.    {id: 3, discount_percent:10, quantity:10, title:"Tier 3"},
  5.    {id: 4, discount_percent:12, quantity:12, title:"Tier 4"},
  6.    {id: 5, discount_percent:14, quantity:14, title:"Tier 5"},
  7.    {id: 6, discount_percent:20, quantity:16, title:"Tier 6"},
  8.    {id: 7, discount_percent:40, quantity:18, title:"Tier 7"},
  9.    {id: 8, discount_percent:50, quantity:50, title:"Tier 8"},
  10. ]
  11. function calculateDiscount(ordersQuanity){
  12.    const bestTier = tiers.reduce((a, tier) => (
  13.      tier.quantity <= ordersQuanity && (!a || tier.discount_percent > a.discount_percent)
  14.        ? tier
  15.        : a
  16.    ), null) || tiers[0]; // alternate with the first element of the array
  17.    // if you want to default to that tier even if the quantity isn't sufficient
  18.    console.log(bestTier);
  19. }
  20. calculateDiscount(10);
  21. calculateDiscount(20);
英文:

For the generic situation of a number of objects with discount_percents and quantitys, .find isn't the right approach because it'll stop as soon as it finds a match. Consider .reduce instead - if an element being iterated over passes the test and it has a greater discount_percent than the current element in the accumulator (if there's anything in the accumulator to begin with), return it instead.

<!-- begin snippet: js hide: false console: true babel: false -->

<!-- language: lang-js -->

  1. let tiers = [
  2.    {id: 1, discount_percent:0, quantity:6, title:&quot;Tier 1&quot;},
  3.    {id: 2, discount_percent:5, quantity:8, title:&quot;Tier 2&quot;},
  4.    {id: 3, discount_percent:10, quantity:10, title:&quot;Tier 3&quot;},
  5.    {id: 4, discount_percent:12, quantity:12, title:&quot;Tier 4&quot;},
  6. ]
  7. function calculateDiscount(){
  8.    const ordersQuanity = 10;
  9.    const bestTier = tiers.reduce((a, tier) =&gt; (
  10.      tier.quantity &lt;= ordersQuanity &amp;&amp; (!a || tier.discount_percent &gt; a.discount_percent)
  11.        ? tier
  12.        : a
  13.    ), null) || tiers[0]; // alternate with the first element of the array
  14.    // if you want to default to that tier even if the quantity isn&#39;t sufficient
  15.    console.log(bestTier);
  16. }
  17. calculateDiscount();

<!-- end snippet -->

If you happen to be able to assume that every increased discount_percent comes with a larger quantity, and the array is sorted, you can use .find if you reverse the array first (so that the items with the greatest discount_percent are iterated over first).

<!-- begin snippet: js hide: false console: true babel: false -->

<!-- language: lang-js -->

  1. let tiers = [
  2.    {id: 1, discount_percent:0, quantity:6, title:&quot;Tier 1&quot;},
  3.    {id: 2, discount_percent:5, quantity:8, title:&quot;Tier 2&quot;},
  4.    {id: 3, discount_percent:10, quantity:10, title:&quot;Tier 3&quot;},
  5.    {id: 4, discount_percent:12, quantity:12, title:&quot;Tier 4&quot;},
  6. ];
  7. const tiersReversed = [...tiers].reverse();
  8. function calculateDiscount(){
  9.    const ordersQuanity = 10;
  10.    const tier = tiersReversed
  11.      .find((_tier) =&gt; _tier.quantity &lt;= ordersQuanity)
  12.       || tiers[0]; // alternate with the first element of the array
  13.    // if you want to default to that tier even if the quantity isn&#39;t sufficient
  14.    console.log(tier);
  15. }
  16. calculateDiscount();

<!-- end snippet -->

The snippet works just as well for the dataset in the edited question.

<!-- begin snippet: js hide: false console: true babel: false -->

<!-- language: lang-js -->

  1. let tiers = [
  2.    {id: 1, discount_percent:0, quantity:6, title:&quot;Tier 1&quot;},
  3.    {id: 2, discount_percent:5, quantity:8, title:&quot;Tier 2&quot;},
  4.    {id: 3, discount_percent:10, quantity:10, title:&quot;Tier 3&quot;},
  5.    {id: 4, discount_percent:12, quantity:12, title:&quot;Tier 4&quot;},
  6.    {id: 5, discount_percent:14, quantity:14, title:&quot;Tier 5&quot;},
  7.    {id: 6, discount_percent:20, quantity:16, title:&quot;Tier 6&quot;},
  8.    {id: 7, discount_percent:40, quantity:18, title:&quot;Tier 7&quot;},
  9.    {id: 8, discount_percent:50, quantity:50, title:&quot;Tier 8&quot;},
  10. ]
  11. function calculateDiscount(ordersQuanity){
  12.    const bestTier = tiers.reduce((a, tier) =&gt; (
  13.      tier.quantity &lt;= ordersQuanity &amp;&amp; (!a || tier.discount_percent &gt; a.discount_percent)
  14.        ? tier
  15.        : a
  16.    ), null) || tiers[0]; // alternate with the first element of the array
  17.    // if you want to default to that tier even if the quantity isn&#39;t sufficient
  18.    console.log(bestTier);
  19. }
  20. calculateDiscount(10);
  21. calculateDiscount(20);

<!-- end snippet -->

答案2

得分: 0

  1. function discountPercent(item){
  2.   return item.discount_percent == 10
  3. }
  5. console.log(tiers.find(discountPercent))
英文:

`function discountPercent(item){
return item.discount_percent == 10
}

console.log(tiers.find(discountPercent))

huangapple
  • 本文由 发表于 2023年1月6日 14:00:10
  • 转载请务必保留本文链接：https://go.coder-hub.com/75027459.html
  • arrays
  • javascript
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