How can I create an Array of objects from arr array in javascript using spread operator? – Trying to fit all of the code on to one line

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英文:

How can I create an Array of objects from arr array in javascript using spread operator? - Trying to fit all of the code on to one line

问题

需要为每个objectid创建一个对象，并为该对象创建一个联系人数组。
我已经完成了不使用展开运算符的代码，但想知道如何使用展开运算符来完成这个任务。

  1. // 我的工作代码，不使用展开运算符
  2. let res = Object.values(
  3.   arr.reduce((acc, { objectid, userid, associationid }) => {
  4.     (acc[objectid] ??= { objectid, contacts: [] }).contacts
  5.       .push({ isdelete: '1', contactid: userid, associationid });
  6.     return acc;
  7.   }, {})
  8. );
  9. console.log(res);
  11. // 尝试以下使用展开运算符的代码，但不起作用
  12. const res = arr.reduce((acc, { objectid, userid, associationid }) =>
  13.   ({ ...acc, (acc[objectid] ??= { objectid, contacts: [] }).contacts.push({ isdelete: '1', contactid: userid, associationid }) }),
  14.   {})
  15.   
  16. console.log(res);
英文:

Need to create one object per objectid and create an array of contacts for that object.
I have done it without spread operator but wondering how this can be done using spread operator.

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

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

  1. const arr = [
  2.   {
  3.     &quot;objectid&quot;: 1,
  4.     &quot;userid&quot;: &quot;1&quot;,
  5.     &quot;associationid&quot;: &quot;123&quot;
  6.   },
  7.   {
  8.     &quot;objectid&quot;: 1,
  9.     &quot;userid&quot;: &quot;2&quot;,
  10.     &quot;associationid&quot;: &quot;456&quot;
  11.   },  
  12.   {
  13.     &quot;objectid&quot;: 2,
  14.     &quot;userid&quot;: &quot;2&quot;,
  15.     &quot;associationid&quot;: &quot;456&quot;
  16.   }
  17. ];

//My working code without using spread operator
let res = Object.values(
arr.reduce((acc, {objectid, userid, associationid}) => {
(acc[objectid] ??= {objectid, contacts : []}).contacts
.push({isdelete: '1', contactid: userid, associationid});
return acc;
}, {})
);
console.log(res);

  1. //Tried the following code using spread operator but not working
  2. const res = arr.reduce((acc, {objectid,userid,associationid}) =&gt;
  3.   ({ ...acc, (acc[objectid] ??= {objectid, contacts : []}).contacts.push({isdelete: &#39;1&#39;, contactid: userid, associationid}) }),
  4.   {})
  5.   
  6. console.log(res);

<!-- end snippet -->

答案1

得分: 1

你试图在同时展开对象的情况下对对象中的数组进行变异，这在语法上是不正确的。我正在使用展开运算符来保留先前的联系人并添加新的联系人。

英文:

You are trying to mutate an array within an object while spreading the object at the same time, which is syntactically incorrect. I am using the spread operator to keep the previous contacts and add the new one.

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

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

  1. const arr = [{
  2.     &quot;objectid&quot;: 1,
  3.     &quot;userid&quot;: &quot;1&quot;,
  4.     &quot;associationid&quot;: &quot;123&quot;
  5.   },
  6.   {
  7.     &quot;objectid&quot;: 1,
  8.     &quot;userid&quot;: &quot;2&quot;,
  9.     &quot;associationid&quot;: &quot;456&quot;
  10.   },
  11.   {
  12.     &quot;objectid&quot;: 2,
  13.     &quot;userid&quot;: &quot;2&quot;,
  14.     &quot;associationid&quot;: &quot;456&quot;
  15.   }
  16. ];
  18. const res = arr.reduce((acc, {
  19.   objectid,
  20.   userid,
  21.   associationid
  22. }) =&gt; {
  23.   if (!acc[objectid]) {
  24.     acc[objectid] = {
  25.       objectid,
  26.       contacts: []
  27.     };
  28.   }
  30.   return {
  31.     ...acc,
  32.     [objectid]: {
  33.       ...acc[objectid],
  34.       contacts: [
  35.         ...acc[objectid].contacts,
  36.         {
  37.           isdelete: &#39;1&#39;,
  38.           contactid: userid,
  39.           associationid
  40.         }
  41.       ]
  42.     }
  43.   };
  44. }, {});
  46. console.log(Object.values(res));

<!-- end snippet -->

答案2

得分: 1

以下是您要翻译的内容：

  1. 您可以尝试这段代码，我希望它能回答您的问题
  3. // 开始代码片段
  4. const arr = [{
  5.     "objectid": 1,
  6.     "userid": "1",
  7.     "associationid": "123"
  8.   },
  9.   {
  10.     "objectid": 1,
  11.     "userid": "2",
  12.     "associationid": "456"
  13.   },
  14.   {
  15.     "objectid": 2,
  16.     "userid": "2",
  17.     "associationid": "456"
  18.   }
  19. ];
  21. const res = Object.values(
  22.   arr.reduce((acc, {
  23.     objectid,
  24.     userid,
  25.     associationid
  26.   }) => {
  27.     acc[objectid] = {
  28.       ...acc[objectid],
  29.       objectid,
  30.       contacts: [
  31.         ...(acc[objectid]?.contacts ?? []),
  32.         {
  33.           isdelete: '1',
  34.           contactid: userid,
  35.           associationid
  36.         },
  37.       ],
  38.     };
  39.     return acc;
  40.   }, {})
  41. );
  43. console.log(res);
  44. // 结束代码片段
英文:

You can try this code I hope it answers your question

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

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

  1. const arr = [{
  2.     &quot;objectid&quot;: 1,
  3.     &quot;userid&quot;: &quot;1&quot;,
  4.     &quot;associationid&quot;: &quot;123&quot;
  5.   },
  6.   {
  7.     &quot;objectid&quot;: 1,
  8.     &quot;userid&quot;: &quot;2&quot;,
  9.     &quot;associationid&quot;: &quot;456&quot;
  10.   },
  11.   {
  12.     &quot;objectid&quot;: 2,
  13.     &quot;userid&quot;: &quot;2&quot;,
  14.     &quot;associationid&quot;: &quot;456&quot;
  15.   }
  16. ];
  18. const res = Object.values(
  19.   arr.reduce((acc, {
  20.     objectid,
  21.     userid,
  22.     associationid
  23.   }) =&gt; {
  24.     acc[objectid] = {
  25.       ...acc[objectid],
  26.       objectid,
  27.       contacts: [
  28.         ...(acc[objectid]?.contacts ?? []),
  29.         {
  30.           isdelete: &#39;1&#39;,
  31.           contactid: userid,
  32.           associationid
  33.         },
  34.       ],
  35.     };
  36.     return acc;
  37.   }, {})
  38. );
  40. console.log(res);

<!-- end snippet -->

答案3

得分: -2

你可以使用逗号运算符在修改累加器后始终返回它。

  1. const arr=[{objectid:1,userid:"1",associationid:"123"},{objectid:1,userid:"2",associationid:"456"},{objectid:2,userid:"2",associationid:"456"}];
  2. let res = Object.values(
  3.   arr.reduce((acc, {objectid, userid, associationid}) => 
  4.     ((acc[objectid] ??= {objectid, contacts : []}).contacts
  5.       .push({isdelete: '1', contactid: userid, associationid}), acc), {})
  6. );
  7. console.log(res);
英文:

You can use the comma operator to always return the accumulator after modifying it.

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

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

  1. const arr=[{objectid:1,userid:&quot;1&quot;,associationid:&quot;123&quot;},{objectid:1,userid:&quot;2&quot;,associationid:&quot;456&quot;},{objectid:2,userid:&quot;2&quot;,associationid:&quot;456&quot;}];
  2. let res = Object.values(
  3.   arr.reduce((acc, {objectid, userid, associationid}) =&gt; 
  4.     ((acc[objectid] ??= {objectid, contacts : []}).contacts
  5.       .push({isdelete: &#39;1&#39;, contactid: userid, associationid}), acc), {})
  6. );
  7. console.log(res);

<!-- end snippet -->

huangapple
  • 本文由 发表于 2023年5月15日 01:34:35
  • 转载请务必保留本文链接：https://go.coder-hub.com/76248858.html
  • javascript
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