Node.js · Theory

fs.filehandle.truncate() method

Theory

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fs.filehandle.truncate() method

If you can teach fs.filehandle.truncate() method using read a big CSV, you know it. If you only know the heading, you don’t.

For fs.filehandle.truncate() method, an Express route is in play. Don’t blame it until you have traced read a big CSV.

Skip fs.filehandle.truncate() method and loading the whole file into RAM shows up in an upload job.

Use fs.filehandle.truncate() method when read a big CSV must stay clear. If a simpler Node.js step works, use that instead.

If read a big CSV breaks under fs.filehandle.truncate() method, check loading the whole file into RAM first.

Place fs.filehandle.truncate() method next to nearby Node.js work — createReadStream is the link.

Viva for fs.filehandle.truncate() method: what it is → createReadStream → the mistake (loading the whole file into RAM).

Exam tip

Board: read a big CSV. Dry-run fs.filehandle.truncate() method. Name the trap: loading the whole file into RAM.

Example

const fs = require("fs");
const path = require("path");

const file = path.join(__dirname || ".", "demo.txt");
fs.writeFileSync(file, "hello node\n");
const text = fs.readFileSync(file, "utf8");
console.log(text.trim());
fs.unlinkSync(file);

fs.filehandle.truncate() method — fs reads/writes files. Prefer promises/async APIs in real apps.

Short notes

Deffs.filehandle.truncate() method — Isha uses it for read a big CSV in an upload job.
Rulefs.filehandle.truncate() method → createReadStream.
Rememberfs.filehandle.truncate() method + an Express route (an upload job).
Usefs.filehandle.truncate() method in an upload job (read a big CSV).
Trapfs.filehandle.truncate() method — loading the whole file into RAM.
Exfs.filehandle.truncate() method → read a big CSV.

const fs = require("fs"); const path = require("path"); const file = path.join(__dirname || ".", "demo.txt"); fs.writeFileSync(file, "hello node\n"); const text = fs.readFileSync(file, "utf8"); console.log(text.trim()); fs.unlinkSync(file);

fs.filehandle.truncate() method

Example

Short notes

Questions

fs.filehandle.truncate() method

Example

Short notes

Questions