在nodejs中寫一個json文件

尼尚·庫馬爾

我有由一組數據組成的現有 products.json 數據，我想在 post 請求上推送一個新的 json 對象。雖然 json 對像數組得到更新，但是當我打開 product.json 文件時，我沒有在該文件中看到新添加的數據。我收到這樣的錯誤

[Error: ENOENT: no such file or directory, open '../data/products.json'] {
  errno: -2,
  code: 'ENOENT',
  syscall: 'open',
  path: '../data/products.json'
}

文件夾結構

 controllers
     productController.js
models
     productModels.js 
data
   products.js
node_modules
package.json
package-lock.json
server.js

產品控制器文件

export const createProduct = async (req, res) => {
    try{
        const product = {
            userId: 'req.userId',
            id: 'req.id',
            title: 'req.title',
            body: 'req.body'
        }
        const newProduct = await create(product)
        res.writeHead(201, { 'Content-Type': 'application/json' });
        res.end(JSON.stringify(newProduct))
    }catch(err){
        console.log(err)
    }
}

產品型號文件

export const create = (product) => {
    const id = uuid()
    const newProduct = {...product, id}
    products.push(newProduct)

    writeDataToFile('../data/products.json', products)

    const promise = new Promise((resolve, reject) => {
        const newProduct = products.find(element => element.id = id)
        setTimeout(() => {
            resolve(newProduct)
        }, 1000)
    })
    return promise
}

utils.js 文件

import { writeFile } from 'fs/promises';

export const writeDataToFile = async (filename, content) => {
    try {
        console.log(filename)
        console.log(process.cwd())
        await writeFile(filename, JSON.stringify(content));      
      } catch (err) {
        console.error(err);
      }
}

阿普爾瓦·奇卡拉

似乎路徑不正確，這就是它不更新文件的原因。


import { writeFile } from 'fs/promises';
import * as path from 'path';

import { fileURLToPath } from 'url';
import { dirname } from 'path';

const __filename = fileURLToPath(import.meta.url);
const __dirname = dirname(__filename);

export const writeDataToFile = async (filename, content) => {
    try {
        console.log(filename)
        console.log(process.cwd());
        console.log(path.join(__dirname, filename)) // check if the path is correct
        await writeFile(path.join(__dirname, filename), JSON.stringify(content));      
     return 'File Updated';
      } catch (err) {
        console.error(err);
      }
}

您可能需要等待文件操作執行：


export const create = (product) => {
    const id = uuid()
    const newProduct = {...product, id}
    products.push(newProduct)

    await writeDataToFile('../data/products.json', products)

    const promise = new Promise((resolve, reject) => {
        const newProduct = products.find(element => element.id = id)
        setTimeout(() => {
            resolve(newProduct)
        }, 1000)
    })
    return promise
}