Node.js · Theory

fs.filehandle.truncate() method

Theory

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fs.filehandle.truncate() method

fs.filehandle.truncate() method is a Node.js topic. In plain words you use it for read a big CSV in an upload job. Don’t start with a slogan — start with that picture.

Smallest example: createReadStream. Type it, run it, and say what you see. If you can do that from memory, you know fs.filehandle.truncate() method.

From the example next to this theory: fs.filehandle.truncate() method — fs reads/writes files. Prefer promises/async APIs in real apps..

Trap — loading the whole file into RAM. Fix that before you talk about advanced Node.js.

Viva — what is fs.filehandle.truncate() method? Then show createReadStream. Then name the trap.

Exam tip

What is fs.filehandle.truncate() method? Show this: createReadStream. 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 — read a big CSV in an upload job.
RulecreateReadStream
Traploading the whole file into RAM
Usean upload job

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