Introduction to capture-console

capture-console is a powerful Node.js library designed to intercept and manipulate console output. This is extremely useful for debugging, logging, and testing purposes.

API Examples

Basic Usage

To use capture-console, you first need to install the library:

  npm install capture-console

Here’s how you can capture console output:

  
const capture = require('capture-console');

capture.startCapture(process.stdout, function stdoutLogger(stdoutOutput) {
    console.log("Captured:", stdoutOutput);
});

console.log("Hello, world!");

capture.stopCapture(process.stdout);
  

Capturing Console.error

You can also capture console.error using:

  
capture.startCapture(process.stderr, function stderrLogger(stderrOutput) {
    console.error("Captured:", stderrOutput);
});

console.error("An error occurred!");

capture.stopCapture(process.stderr);
  

Capturing Both stdout and stderr

To capture both stdout and stderr:

  
capture.startCapture(process.stdout, function(stdoutOutput) {
    console.log("Captured stdout:", stdoutOutput);
});

capture.startCapture(process.stderr, function(stderrOutput) {
    console.log("Captured stderr:", stderrOutput);
});

console.log("Hello, world!");
console.error("An error occurred!");

capture.stopCapture(process.stdout);
capture.stopCapture(process.stderr);
  

Saving Captured Output to a File

You can conveniently save the captured output to a file:

  
const fs = require('fs');
const capture = require('capture-console');
const outputLog = fs.createWriteStream('output.log');

capture.startCapture(process.stdout, function(stdoutOutput) {
    outputLog.write(stdoutOutput);
});

console.log("Logging to a file!");

capture.stopCapture(process.stdout);
outputLog.end();
  

App Example Using `capture-console`

Logging all outputs to a file

Here’s a simple example of a Node.js app logging both stdout and stderr to a file:

  
const fs = require('fs');
const capture = require('capture-console');
const logStream = fs.createWriteStream('app.log');

capture.startCapture(process.stdout, function(stdoutOutput) {
    logStream.write(`stdout: ${stdoutOutput}\n`);
});

capture.startCapture(process.stderr, function(stderrOutput) {
    logStream.write(`stderr: ${stderrOutput}\n`);
});

console.log("Starting the app...");
console.error("Oops, an error occurred!");
console.log("Finishing up...");

capture.stopCapture(process.stdout);
capture.stopCapture(process.stderr);
logStream.end();
  

Using the capture-console library, you can effectively manage and analyze your application’s log output, making debugging and testing more straightforward and efficient.

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