nodejs-mozilla/test/parallel/test-fs-promises-file-handl...

26 lines
736 B
JavaScript

'use strict';
const common = require('../common');
const assert = require('assert');
const path = require('path');
const { open, readFile } = require('fs').promises;
const tmpdir = require('../common/tmpdir');
tmpdir.refresh();
async function validateTruncate() {
const text = 'Hello world';
const filename = path.resolve(tmpdir.path, 'truncate-file.txt');
const fileHandle = await open(filename, 'w+');
const buffer = Buffer.from(text, 'utf8');
await fileHandle.write(buffer, 0, buffer.length);
assert.deepStrictEqual((await readFile(filename)).toString(), text);
await fileHandle.truncate(5);
assert.deepStrictEqual((await readFile(filename)).toString(), 'Hello');
}
validateTruncate().then(common.mustCall());