Node.js script.createCachedData() Method

The script.createCachedData() method is an inbuilt application programming interface of script module which is used to create a code cache that can be used with the cachedData option of the script constructor. It can be called at any time and any number of times.
Syntax:

script.createCachedData()

Parameters: This method doesn’t accept any parameters.
Return Value: It returns buffer.
Below examples illustrate the use of script.createCachedData() method in Node.js:
Example 1:

javascript

// Node.js program to demonstrate the
// script.createCachedData() method

// Including vm module
const vm = require("vm");

// Constructing script and defining a
// function add inside it
const script = new vm.Script(`

function add(a, b) {
  return a + b;
}

const x = add(1, 2);
`);

// Calling createCachedData without caching
// the variable x used above
const cacheWithoutx = script.createCachedData();
console.log(cacheWithoutx);

Output:

<Buffer b5 03 de c0 8a f4 d4 f4 3f 00 00 00
ff 03 00 00 d5 a2 f5 b7 06 00 00 00 00 00 00 
00 28 02 00 00 af 79 f4 0d a0 8c bf b8 00 00
00 80 20 0000 80 00 03 ... >

Example 2:

javascript

// Node.js program to demonstrate the
// script.createCachedData() method

// Including vm module
const vm = require("vm");

// Constructing script and defining a
// function add inside it
const script = new vm.Script(`

function add(a, b) {
  return a + b;
}

const x = add(1, 2);
`);

// Calling runInThisContext method
script.runInThisContext();

// Calling createCachedData with caching
// the variable x used above
const cacheWithx = script.createCachedData();
console.log(cacheWithx);

Output:

<Buffer b5 03 de c0 8a f4 d4 f4 3f 00
00 00 ff 03 00 00 d5 a2 f5 b7 06 00 00 00 00
00 00 00 00 03 00 00 03 67 df 75 6d 4c 36 07
00 00 00 80 20 0000 80 38 04 ... >

Reference: https://nodejs.org/api/vm.html#vm_script_createcacheddata