javascript - Node.js TypeError：路径必须是字符串或缓冲区

Question

我正在编写一个命令行程序，它使用 CSV 文件中的信息计算订单的总价格。

sample.catalog.csv 中的数据：

P1,5,1000.00
P2,8,250.00
P3,15,125.00
P4,10,250.00
P5,2,2500.00

并且程序必须使用以下参数从命令行运行：

示例：$ CalculateOrder sample.catalog.csv P1 2 P2 4

（P4 6 P10 5 P12 1 是 csv 文件中提供的产品和数量）

总计：4151,25

这就是我目前所拥有的：

var program = require('commander');
const csv = require('csv');
const fs = require('fs');


program
    .version('1.0.0')
    .option('-l, --list [list]', 'list of order prices in sample.catalog.csv')
    .parse(process.argv)

console.log("hello world")
console.log("list of order prices", program.list);


/* 
    To read csv file and print the data to the console:
    [node orderPrice --list input/sample.catalog.csv]
*/

let parse = csv.parse;
let stream = fs.createReadStream(program.list)
    .pipe(parse({ delimiter: ',' }));

var total = 0;
const vat = 23;
const totalWithVat = total * vat;

stream
.on('data', function (data) {
    let product = data[0];
    let quantity = data[1];
    let price = data[2];
    console.log(product, quantity, price);
    calculateOrder = () => {
        if (quantity > 20) {
            stream.destroy(new Error("Quantity exceeds stored amounts"));
        }
        total += price * quantity;
    }
})

.on("finish", function () {
    console.log("Total price:", totalWithVat);
})

.on("error", function (error) {
    console.error("The following error occured:", error);
})

我有以下错误：

λ node orderPrice calculateOrder sample.catalog.csv P1 2 P2 4
hello world
list of order prices undefined
fs.js:636
binding.open(pathModule._makeLong(path),
      ^

TypeError: path must be a string or Buffer
    at Object.fs.open (fs.js:636:11)
    at ReadStream.open (fs.js:1982:6)
    at new ReadStream (fs.js:1969:10)
    at Object.fs.createReadStream (fs.js:1923:10)
    at Object.<anonymous> (E:\order-price\orderPrice.js:31:17)
    at Module._compile (module.js:643:30)
    at Object.Module._extensions..js (module.js:654:10)
    at Module.load (module.js:556:32)
    at tryModuleLoad (module.js:499:12)
    at Function.Module._load (module.js:491:3)

我是一个 Node.js 新手，非常感谢任何帮助。谢谢你。

标签： javascriptnode.jscommand-line

Answer 1

换线

let stream = fs.createReadStream(program.list)

到

let stream = fs.createReadStream(program.argv[some number])

其中一些数字是您提到文件名的位置

例如使用以下命令运行程序

node test.js somevar filename

那么某个数字 = 3

0th param > node
1st param > test.js (file to run)
2nd > somevar
3rd > filename

另一个错误：

最终代码看起来像

const csv = require('fast-csv');
const fs = require('fs');

console.log("hello world")
console.log("list of order prices", process.argv[2]);
let required_products=[]
for(var i=3;i<process.argv.length;){
   let temp=[]
   temp.name=process.argv[i++]
   temp.quantity=process.argv[i++]
   required_products.push(temp)
}
/*
    To read csv file and print the data to the console:
    [node orderPrice --list input/sample.catalog.csv]
*/

let stream = fs.createReadStream(process.argv[2]);

var total = 0;
var csvStream = csv()
    .on("data", function(data){
         let product_name = data[0];
         let quantity = data[1];
         let price = data[2];

         required_products.forEach(function(product){

             if(product['name']==product_name){
               if(parseInt(product['quantity'])>parseInt(quantity)){
                 console.log('Quantity required for product '+product['name']+' '+product['quantity']+' is greater than available '+quantity);
                 process.exit(1)
               }else{
                 total += parseInt(price) * parseInt(product['quantity']);
               }
             }
         })
    })
    .on("end", function(){
         console.log("done");
         let totalWithVat = total * (1+ 0.23);
         console.log("Total price:", totalWithVat);
    }).on("error", function (error) {
        console.error("The following error occured:", error);
    })
 stream.pipe(csvStream);