CODEWITHSUNDEEP
javascriptnode.jsreadfile
Andreas
Andreas

Reputation: 1287

Reading line from file doesn't return the correct string with fs.readFileSync

When reading a file line by line with below code. It seems to not read the string correctly?

Part of the String on each line in file is this:
b53pd4574z8pe9x793go

console.log(pathcreatefile) correctly shows:
b53pd4574z8pe9x793go

But is seems that: fs.promises.writeFile does this?:
b53'd4574z8pe9x793go

Console error is this:
(node:1148) UnhandledPromiseRejectionWarning: Error: ENOENT: no such file or directory, open 'C:\myproject\instances\b53'd4574z8pe9x793go\folder\testA.txt

My code is the below. I have added the 3 lines I read from the file in the code:

'use strict';
const fs = require('fs');
var i;


//1|one/a|test1|C:/myproject/instances/b53pd4574z8pe9x793go/folder/testA.txt
//1|two/b|test2|C:/myproject/instances/b53pd4574z8pe9x793go/folder/testB.txt
//1|three/c|test3|C:/myproject/instances/b53pd4574z8pe9x793go/folder/testC.txt
var textarray = fs.readFileSync("C:/myproject/folder/testfile.txt").toString('utf-8').split("\n"); //Read the file


(async () => {
    var thePromises = []
    for (i = 0; i < textarray.length; i++) {

        //1|one/a|test1|C:/myproject/instances/b53pd4574z8pe9x793go/folder/testA.txt
        const line = textarray[i].split("|")
        if (line.length == 4) {

            const pathcreatefile = line[3] //C:/myproject/instances/b53pd4574z8pe9x793go/folder/testA.txt
            console.log(pathcreatefile)

            try {
                    let tickerProcessing = new Promise(async (resolve) => {
                    await fs.promises.writeFile(pathcreatefile, "hello")
                    resolve()
                })
                thePromises.push(tickerProcessing)

            } catch (e) {
                console.error(e)
            }
        }
    }

    // wait for all of them to execute or fail
    await Promise.all(thePromises)
    })()

Upvotes: 4

Views: 388

Answers (1)

Igor Litvinovich
Igor Litvinovich

Reputation: 2502

There is no need to wrap fs.promises.writeFile into an extra Promise, it returns Promise without any wrappers.

Also you should the constant from 'os' package for line separator to make it work across different operating systems. The following code will work for you:

         'use strict';
var endOfLine = require('os').EOL;
const fs = require('fs');
var textarray = fs.readFileSync("./testfile.txt").toString('utf-8').split(endOfLine);
(async () => {
    await Promise.all(textarray.map((textElement) => {
        const line = textElement.split("|")
        if (line.length === 4) {
            const pathcreatefile = line[3] 
            console.log(pathcreatefile)
            return fs.promises.writeFile(pathcreatefile, "hello")
        }
    }));
})()

Upvotes: 2

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