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如何在 JavaScript 中分離每個 JSON 對象并將它們分組到一個數組中？

JavaScript

開滿天機 2023-09-21 16:45:49

來自 multer.js 的 req.files 示例[ { fieldname: files0, originalname: 'Screenshot from 2020-05-23 01-52-30.png', encoding: '7bit', mimetype: 'image/png', destination: 'public/uploads/projects/0a480789-eb14-4fe4-bb89-44aa741efe33/proposals/chma00000133', filename: '1606822252923_Screenshot from 2020-05-23 01-52-30.png', path: 'public/uploads/projects/0a480789-eb14-4fe4-bb89-44aa741efe33/proposals/chma00000133/1606822252923_Screenshot from 2020-05-23 01-52-30.png', size: 172092 }, { fieldname: files0, originalname: 'Screenshot from 2020-05-22 08-44-05.png', encoding: '7bit', mimetype: 'image/png', destination: 'public/uploads/projects/0a480789-eb14-4fe4-bb89-44aa741efe33/proposals/chma00000133', filename: '1606822252925_Screenshot from 2020-05-22 08-44-05.png', path: 'public/uploads/projects/0a480789-eb14-4fe4-bb89-44aa741efe33/proposals/chma00000133/1606822252925_Screenshot from 2020-05-22 08-44-05.png', size: 440592 }, { fieldname: files1, originalname: 'Screenshot from 2020-05-30 11-36-42.png', encoding: '7bit', mimetype: 'image/png', destination: 'public/uploads/projects/0a480789-eb14-4fe4-bb89-44aa741efe33/proposals/chma00000133', filename: '1606822252930_Screenshot from 2020-05-30 11-36-42.png', path: 'public/uploads/projects/0a480789-eb14-4fe4-bb89-44aa741efe33/proposals/chma00000133/1606822252930_Screenshot from 2020-05-30 11-36-42.png', size: 477511 },我想動態地將每個 JSON 對象與其字段名分組，并將它們存儲在對象數組中，同時使用它們的字段名編號作為數組索引。組可以在 0 到 9 之間，具體取決于用戶輸入。

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3 回答

瀟瀟雨雨

TA貢獻1833條經驗獲得超4個贊

我會使用減少

const data = [?

{ fieldname: 'files0', originalname: 'Screenshot from 2020-05-23 01-52-30.png', },

{ fieldname: 'files0', originalname: 'Screenshot from 2020-05-22 08-44-05.png', },

{ fieldname: 'files1', originalname: 'Screenshot from 2020-05-30 11-36-42.png', },

{ fieldname: 'files1', originalname: 'Screenshot from 2020-05-30 11-36-36.png', },

{ fieldname: 'files1', originalname: 'Screenshot from 2020-05-30 11-36-31.png', }],

arr = data.reduce((acc, cur) => {

? const idx = cur.fieldname.replace("files",""); // get 0, 1

? if (acc[idx]) acc[idx].push(cur); // if already there, just push

? else acc[idx] = [cur];? ? ? ? ? ? // otherwise initialise

? return acc;

},[])?

console.log(arr)

注意：組可以在 0 到 9 之間，具體取決于用戶輸入。

我假設沒有漏洞，因為這可能會導致稀疏數組，所以

data = [?

? ? ?{ fieldname : 'files0' },

? ? ?{ fieldname : 'files3' },

會創建一個數組

[

? [ { fieldname : 'files0' }, { fieldname : 'files0' } ],

? null,

? [ { fieldname : 'files3' }, { fieldname : 'files3' } ],

]

反對回復 2023-09-21

肥皂起泡泡

TA貢獻1829條經驗獲得超6個贊

我盡量不修改你的邏輯來做到這一點。

如果沒有files2，filesArray[2] 將為undefined。

// Omit other fields

const req = {

files: [

{ fieldname: "files0", originalname: 'Screenshot from 2020-05-23 01-52-30.png'},

{ fieldname: "files0", originalname: 'Screenshot from 2020-05-22 08-44-05.png'},

{ fieldname: "files1", originalname: 'Screenshot from 2020-05-30 11-36-42.png'},

{ fieldname: "files1", originalname: 'Screenshot from 2020-05-30 11-36-36.png'},

{ fieldname: "files1", originalname: 'Screenshot from 2020-05-30 11-36-31.png'},

{ fieldname: "files3", originalname: 'Screenshot from 2020-05-30 11-36-42.png'},

{ fieldname: "files3", originalname: 'Screenshot from 2020-05-30 11-36-36.png'},

{ fieldname: "files3", originalname: 'Screenshot from 2020-05-30 11-36-31.png'}

]

}

let filesArray = []

for (let file of req.files) {

const thisFileGroup = parseInt(file.fieldname.match(/\d/g).join(''), 10);

if (!filesArray[thisFileGroup]) {

filesArray[thisFileGroup] = []

}

filesArray[thisFileGroup].push(file)

}

console.log(filesArray[2]) // will be undefined

console.log(filesArray[1]) // will be files1 array

console.log(filesArray)

反對回復 2023-09-21

DIEA

TA貢獻1820條經驗獲得超2個贊

如果您不一定需要按索引排序files[index]

在這種情況下，你可以將Array.prototype.reduce()轉換為Object。
您的對象將按屬性（但不是按字母順序）分組，其中包含一個數組，其中的項目具有相同的屬性鍵。使用Object.values()?（如果需要，還可以使用Array.prototype.forEach()）?迭代您的對象。fieldname

const data = [

? { fieldname: "files0", originalname: '0-a'},

? { fieldname: "files0", originalname: '0-b'},

? { fieldname: "files1", originalname: '1-a'},

? { fieldname: "files1", originalname: '1-b'},

? { fieldname: "files1", originalname: '1-c'},

];

const byFieldName = data.reduce((ob, d) => {

? if (!ob.hasOwnProperty(d.fieldname)) ob[d.fieldname] = [];

? ob[d.fieldname].push(d);

? return ob;

}, {});

// console.log(byFieldName); // Uncomment to see how it looks like

console.log( Object.values(byFieldName) );

反對回復 2023-09-21

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如何在 JavaScript 中分離每個 JSON 對象并將它們分組到一個數組中？

如何在 JavaScript 中分離每個 JSON 對象并將它們分組到一個數組中？

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如何在 JavaScript 中分離每個 JSON 對象并將它們分組到一個數組中？