Node.js crypto.randomFill() Method
Last Updated :
11 Oct, 2021
Improve
The crypto.randomFill() method is same as crypto.randomBytes() method but the only difference is that here the first argument is
javascript
Output:
javascript
Output:
buffer that will be filled and it also has a callback function passed as an argument. However, if a callback function is not available then the error is thrown.
Syntax:
crypto.randomFill( buffer, offset, size, callback )Parameters: This method accept four parameters as mentioned above and described below:
- buffer: This parameter holds Buffer, TypedArray, or DataView type of data.
- offset: It is a number whose default value is 0.
- size: It is a number whose default value is (buffer.length - offset).
- callback: It is a function with two parameters namely err and buf.
// Node.js program to demonstrate the
// crypto.randomFill() method
// Including crypto module
const crypto = require('crypto');
// Defining buffer
const buf = Buffer.alloc(6);
// Calling randomFill method with two
// of its parameters
crypto.randomFill(buf, (err, buf) => {
if (err) throw err;
// Prints random data in buffer
console.log(buf.toString('ascii'));
});
// Calling randomFill method with all
// its parameters
crypto.randomFill(buf, 3, 2, (err, buf) => {
if (err) throw err;
// Prints random data in buffer
console.log(buf.toString('base64'));
});
// The output of this is same as above
crypto.randomFill(buf, 3, 3, (err, buf) => {
if (err) throw err;
console.log(buf.toString('base64'));
});
&43Jho0s5v0 Jho0s5v0Here, the last two values are same. Example 2:
// Node.js program to demonstrate the
// crypto.randomFill() method
// Including crypto module
const crypto = require('crypto');
// Defining dataview
const datv = new DataView(new ArrayBuffer(6));
// Calling randomFill method with DataView
// instance as buffer
crypto.randomFill(datv, (err, buf) => {
if (err) throw err;
// Prints random data which is encoded
console.log(Buffer.from(buf.buffer,
buf.byteOffset, buf.byteLength)
.toString('ascii'));
});
ceVMbHere, any TypedArray, or DataView instance is passed as buffer and in every run you will get different output. Reference: https://nodejs.org/api/crypto.html#crypto_crypto_randomfill_buffer_offset_size_callback
