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var console: Console

The console module provides a simple debugging console that is similar to the JavaScript console mechanism provided by web browsers.

The module exports two specific components:

  • A Console class with methods such as console.log(), console.error() and console.warn() that can be used to write to any Node.js stream.
  • A global console instance configured to write to process.stdout and process.stderr. The global console can be used without importing the node:console module.

Warning: The global console object's methods are neither consistently synchronous like the browser APIs they resemble, nor are they consistently asynchronous like all other Node.js streams. See the note on process I/O for more information.

Example using the global console:

console.log('hello world');
// Prints: hello world, to stdout
console.log('hello %s', 'world');
// Prints: hello world, to stdout
console.error(new Error('Whoops, something bad happened'));
// Prints error message and stack trace to stderr:
// Error: Whoops, something bad happened
// at [eval]:5:15
// at Script.runInThisContext (node:vm:132:18)
// at Object.runInThisContext (node:vm:309:38)
// at node:internal/process/execution:77:19
// at [eval]-wrapper:6:22
// at evalScript (node:internal/process/execution:76:60)
// at node:internal/main/eval_string:23:3
const name = 'Will Robinson';
console.warn(`Danger ${name}! Danger!`);
// Prints: Danger Will Robinson! Danger!, to stderr

Example using the Console class:

const out = getStreamSomehow();
const err = getStreamSomehow();
const myConsole = new console.Console(out, err);
myConsole.log('hello world');
// Prints: hello world, to out
myConsole.log('hello %s', 'world');
// Prints: hello world, to out
myConsole.error(new Error('Whoops, something bad happened'));
// Prints: [Error: Whoops, something bad happened], to err
const name = 'Will Robinson';
myConsole.warn(`Danger ${name}! Danger!`);
// Prints: Danger Will Robinson! Danger!, to err

@seesource

console
.
Console.log(message?: any, ...optionalParams: any[]): void

Prints to stdout with newline. Multiple arguments can be passed, with the first used as the primary message and all additional used as substitution values similar to printf(3) (the arguments are all passed to util.format()).

const count = 5;
console.log('count: %d', count);
// Prints: count: 5, to stdout
console.log('count:', count);
// Prints: count: 5, to stdout

See util.format() for more information.

@sincev0.1.100

log
((1 + 2 + 3 + 4).to
Number.toFixed(fractionDigits?: number): string

Returns a string representing a number in fixed-point notation.

@paramfractionDigits Number of digits after the decimal point. Must be in the range 0 - 20, inclusive.

Fixed
(2))
toExponential
toFixed
toLocaleString
toPrecision
toString
/** A Basic Todo interface*/
interface
interface Todo

A Basic Todo interface

Todo
{
Todo.title: string
title
: string;
}
const
const todo: Readonly<Todo>
todo
:
type Readonly<T> = { readonly [P in keyof T]: T[P]; }

Make all properties in T readonly

Readonly
<
interface Todo

A Basic Todo interface

Todo
> = {
title: 'Delete inactive users',
title: string
}
const todo: Readonly<Todo>
todo
.title = 'Hello'
Error ts(2540) ― Cannot assign to 'title' because it is a read-only property.