I'm trying to escape quotes in txt file using node.js and regex.
My code looks like this:
const fs = require("fs");
const utf8 = require("utf8");
var dirname = ".\\f\\";
const regex = new RegExp(`(?<=".*)"(?=.*"$)`, "gm");
fs.readFile(dirname + "test.txt", (error, data) => {
if (error) {
throw error;
}
var d = data.toString();
d = utf8.encode(d)
console.log(`File: ${typeof d}`); //string
// d = `Another string\n"Test "here"."\n"Another "here"."\n"And last one here."`;
console.log(`Text: ${typeof d}`); //string
var re = d.replace(regex, '\\"');
console.log(`Result:\n${re}`);
/* Another string
"Test \"here\"."
"Another \"here\"."
"And last one here."
*/
});
The problem is:
When I remove comment from the line, everything works fine. But if i read the text from the file it doesn't want to work.
Thanks for any comments on this.
Well.. turns out the problem was in file encoding. The file was encoded in UTF-16, not in UTF-8. Node.js wasn't giving me any signs of wrong encoding, so well, nice.
Related
I know you can read line-by-line with require('readline'), is there a good way to read a file character by character? Perhaps just use readline and then split the line into characters?
I am trying to convert this code:
const fs = require('fs');
const lines = String(fs.readFileSync(x));
for(const c of lines){
// do what I wanna do with the c
}
looking to make this into something like:
fs.createReadStream().pipe(readCharByChar).on('char', c => {
// do what I wanna do with the c
});
Simple for loop
let data = fs.readFileSync('filepath', 'utf-8');
for (const ch of data){
console.log(ch
}
Using forEach
let data = fs.readFileSync('filepath', 'utf-8');
data.split('').forEach(ch => console.log(ch)
Is it possible to look for files of given extension by the containing string provided?
What should my approach be? For example the input is txt and hello, and the output will be list of all files containing the string hello with extension txt.
You would write this in your terminal: node main.js hello
For a given directory it will search inside all subdirectories and all files for a text file with hello
Here is the code:
const { readdirSync, readFileSync, lstatSync } = require('fs');
const path = require('path');
const getDir = source => {
const results = readdirSync(source);
results.forEach(function (result) {
if (lstatSync(path.join(source, result))
.isFile()) {
if (readFileSync(path.join(source, result))
.includes(argument) && path.extname(result)
.toLowerCase() === extension) {
console.log("Your string is is in file: ", result)
}
}
else if (lstatSync(path.join(source, result))
.isDirectory()) {
getDir(path.join(source, result));
}
});
}
const dir = process.cwd();
const extension = '.txt'; //You can change the extension type here
let argument = process.argv[2];
getDir(dir);
You can use FileSystem to get the contents of a folder with the readdir method, this returns you an array of strings.
Let's say your working directory is a src file, in which there is a files folder that you want to read. Your script would look something like this:
const fs = require('fs');
var files = fs.readdir('./files', (err, filenames) => {
if (err) throw err;
return filenames;
})
You can then separate your string using string methods. Let's say you want to have two variables, fileNameand fileExt
You would use the String.split(separator) method, and use the . character as separator.
var files = // fs snippet above
for (file in files) {
let fileComponents = file.split('.');
let fileName = fileComponents[0];
let fileExt = fileComponents[1];
// You can run your code on the name, and extension of your file here.
}
This will not work for files containing multiple dots in their name. You will need extra work on the array to make sure fileName contains every string concatenated, separated by a . up until the final index of your fileComponents string
I have an array of objects like below that i have to write to a file with node js, the aim is to write one item per line into one file :
cont obj = [{a:1},{b:2}]
Output file content expected :
//file.json
{a:1}
{b:2}
My code without success
jsonfile.writeFileSync(filePath, JSON.stringify(obj), 'utf-8');
/*
* [\{a:1\},\{b:2\}] <=== a string in one line with special characters
* doesn't fit on my need
*/
If someone could helps me,
Thank you.
You could simply:
const text = arr.map(JSON.stringify).reduce((prev, next) => `${prev}\n${next}`);
fs.writeFileSync(filePath, text, 'utf-8');
(That's a slight modification of #ronapelbaum approach)
You can use util.inspect and loop.
const arr = [{a:1}, {b:2}];
const filePath = "path/to/json";
for (let obj of arr)
fs.appendFileSync (filePath, util.inspect (obj) + "\n")
Or, if you'd like to accumulate the data to save on write operations:
const arr = [{a:1}, {b:2}];
const data = arr.reduce ((a, b) => a + util.inspect (b) + "\n", "");
const filePath = "path/to/json";
fs.writeFileSync (filePath, data);
The final file will fit your requirements:
{ a: 1 }
{ b: 2 }
when you're using the jsonfile library, you don't need to use JSON.stringify(obj).
in your case, you don't really want to write a valid json...
consider this:
const text = arr.reduce((txt, cur) => txt + '\n' + JSON.stringify(cur), '');
fs.writeFileSync(filePath, text, 'utf-8');
I would like add string on the top of my js file. Actuly, it's on the end :
var file = './public/js/app.bundleES6.js',
string = '// My string';
fs.appendFileSync(file, string);
Do you have idea for add my string on the first line ?
Thank you !
I think there is no built-in way to insert at the beginning of the file in Node.js.
But you can use readFileSync and writeFile methods of fs to resolve this issue
It will append string at top of the file
Try this
Method#1
var fs = require('fs');
var data = fs.readFileSync('./example.js').toString().split("\n");
data.splice(0, 0, "Append the string whatever you want at top" );
var text = data.join("\n");
fs.writeFile('./example.js', text, function (err) {
if (err) return err;
});
Method#2
If you are relying on to use third party module then you can use prepend module to add the string at the top as suggested by #robertklep.
var prepend = require('prepend');
prepend(FileName, 'String to be appended', function(error) {
if (error)
console.error(error.message);
});
I am trying to parse a string of xml and I getting an error
[Error: Invalid character entity
Line: 0
Column: 837
Char: ]
Does xml not like brackets? Do I need to replace all the brackets with something like \\]. Thanks
Ok, the invalid character was the dash and an &. I fixed it by doing the following:
xml = data.testSteps.replace(/[\n\r]/g, '\\n')
.replace(/&/g,"&")
.replace(/-/g,"-");
Thanks
Using a node domparser will get around having to do a string replace on every character that is not easily parsed as a string. This is especially useful if you have a large amount of XML to parse that may have different characters.
I would recommend xmldom as I have used it successfully with xml2js
The combined usage looks like the following:
var parseString = require('xml2js').parseString;
var DOMParser = require('xmldom').DOMParser;
var xmlString = "<test>some stuff </test>";
var xmlStringSerialized = new DOMParser().parseFromString(xmlString, "text/xml");
parseString(xmlStringSerialized, function (err, result) {
if (err) {
//did not work
} else {
//worked! use JSON.stringify()
var allDone = JSON.stringify(result);
}
});