Webpage Child Process Module

The Phantomjs Child process module helps to interact with the sub-processes and talk to them using stdin /stdout/stderr. The child processes can be used for tasks like printing, sending mail or to invoke programs written in another language. To create a child process module, you need references.

For example −

var process = require("child_process");

Spawn Method

With the spawn child process, you can subscribe to its stdout and stderr streams to get data real-time.

Syntax

Its syntax is as follows −

var spawn = require('child_process').spawn;

Example

Let us look at an example of the spawn method.

var process = require("child_process")
var spawn = process.spawn
var child = spawn("cmd", ['/c', 'dir']);

child.stdout.on("data", function (data) {
   console.log("spawnSTDOUT---VALUE:", JSON.stringify(data))
})
child.stderr.on("data", function (data) {
   console.log("spawnSTDERR:", JSON.stringify(data))
})
child.on("exit", function (code) {
   console.log("spawnEXIT:", code)
})

Output

The above program generates the following output.

spawnSTDOUT---VALUE: " Volume in drive C is OS\r\n"
spawnSTDOUT---VALUE: " Volume Serial Number is 7682-9C1B\r\n\r\n Directory of C:
\\phantomjs\\bin\r\n\r\n"
spawnSTDOUT---VALUE: "20-05-2017  10:01
<DIR>          .\r\n20-05-2017  10:01
<DIR>          ..\r\n13-05-2017  20:48   12 a,txt.txt\r\n07-05-2017  08:51
63 a.js\r\n06-05-2017  16:32           120,232 a.pdf\r\n13-05-2017  20:49 
spawnEXIT: 0