The following global variables exist in Node.js: Global object: global Core module: process, console, require Runtime environment variables: __dirname, __filename, __line, __column Constants: undefined, null, NaN, Infinity, - Infinity
Global variables in Node.js
There are several built-in global variables in Node.js:
1. Global object
-
global: Represents the global object of the currently executing script. All other global variables are properties of this object.
2. Core module
-
#process: Provides detailed information and control of the Node.js process. -
console: Provides console output and debugging functions. -
require: used to load and access other modules.
3. Runtime environment variable
-
#__dirname: Contains the absolute path to the directory where the current module is located. -
__filename: Contains the absolute path of the current module file. -
__line: The line number of the line of code currently being executed. -
__column: The column number of the line of code currently being executed.
4. Constant
-
undefined: Undefined value. -
null: Indicates a null value. -
NaN: non-numeric value. -
Infinity: Positive infinity. -
-Infinity: Negative infinity.
Using global variables
Global variables can be accessed directly from any Node.js script. For example:
console.log(global); console.log(process.pid); console.log(__dirname);
Note:
- Global variables are visible throughout the application and should be used with caution.
- Avoid modifying global variables provided by core modules, as this may cause unexpected behavior.
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