Delete and recreate WriteStream - node.js

Question

In Node.js how can you delete the file a WriteStream was writing to and then recreate the stream without error?
With this code
clear(){
return new Promise((resolve, reject) => {
this.stream.once('close', () => {
Fs.unlinkSync(this.filepath);
this.stream = Fs.createWriteStream(this.filepath, {flags: 'a'});
resolve();
});
this.stream.end();
});
}
This error occurs. I've tried everything.
Uncaught Error: EPERM: operation not permitted, open 'C:\test\test.log'
The calling code
it('erases the log file', async () => {
const file = new File("C:\test\test.log");
await file.clear();
const exists = Fs.existsSync(testfile);
Assert.strictEqual(exists, false);
});
I can only avoid the error if I remove the this.stream = Fs.createWriteStream(this.filepath, {flags: 'a'}); in clear()

Answer 1

When I try to duplicate your issue here, I only get that error if you are not properly waiting for the clear() method to finish before you attempt to use the stream again.
For example, this code works:
const fs = require('fs');
class MyFile {
constructor(filepath) {
this.filepath = filepath;
this.open();
}
open() {
this.stream = fs.createWriteStream(this.filepath, { flags: 'a' });
this.stream.on('error', err => {
console.log(err);
});
}
log(str) {
this.stream.write(str);
}
clear() {
return new Promise((resolve, reject) => {
this.stream.once('close', () => {
console.log("got clear close event");
try {
fs.unlinkSync(this.filepath);
} catch (e) {
console.log(e);
}
this.open();
resolve();
});
this.stream.end();
});
}
close() {
return new Promise((resolve, reject) => {
this.stream.once('close', () => {
console.log("got final close event");
resolve();
});
this.stream.end();
});
}
}
async function run() {
const f = new MyFile("./temp.xxx");
f.log("hello\n");
f.log("goodbye\n");
await f.clear();
f.log("hello\n");
f.log("goodbye\n");
await f.close();
}
run().then(result => {
console.log("done");
}).catch(err => {
console.log(err);
});
But, if I remove the await in front of await f.clear(), then I get your exact error because the code proceeds trying to use the stream after you've called this.stream.end(), but before the new stream is in place which is an EPERM error.
If this doesn't illustrate for you what your problem is, then you need to show us all the rest of the code that uses this class and calls the clear() method. The problem is likely in that code.