Customising Log Outputs

To customise the logs, you can add a helper text to help you describe what kind of logs it is eg the type of data, as well as colors to style the logs according to your preferences, eg red for logging errors

Import statement:

import { println } from "js-logs-formatter";

We will be using the same sample data that was used in the Basic Usage section.

println({
  helper: "User Data",
  data: user,
  color: "green",
});

This will print out the user data with a green color to the console and the logs will also include the function name and line number that the println function was called.

Output:

User Data (called from function: yourFunctionName at line yourLineNumber)
{
  "name": "Jane Doe",
  "age": 28,
  "active": false,
  "email": "janedoe@example.com",
  "phone": "+1234567890",
  "address": {
    "street": "123 Main St",
    "city": "Anytown",
    "state": "CA",
    "zipCode": "12345"
  },
  "preferences": {
    "newsletter": true,
    "notifications": {
      "email": true,
      "sms": false
    }
  },
  "createdAt": "2022-01-15T14:30:00Z",
  "lastLogin": "2023-09-28T10:00:00Z",
  "roles": [
    "user",
    "admin"
  ],
  "points": 1500
}

Note

Due to differences in how React Native handles stack traces, the accuracy of line numbers and function names can vary. While the println function captures file names and line numbers accurately in Node.js environments, in React Native, the stack trace format may include network-related information or different formatting, making line numbers less predictable. For best results, focus on the file name and function name when using this in a React Native environment.

We can use the red color (background colors included) to easily identify error logs:

try {
  loginUser();
} catch (error) {
  println({
    helper: "loginUser error",
    data: error.response.data.message,
    color: "red",
  });
}

Output:

loginUser error
{ 
  "success": false, 
  "error": "Invalid email or password"
}

Or using a red background color:

try {
  loginUser();
} catch (error) {
  println({
    helper: "loginUser error",
    data: error.response.data.message,
    color: "bgRed",
  });
}

loginUser error
{ 
  "success": false, 
  "error": "Invalid email or password"
}