console 控制台


console 模块提供了一个简单的调试控制台,类似于网络浏览器提供的 JavaScript 控制台机制。

    Stability: 2 - Stable

    Source Code: lib/console.js

    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 calling require('console').

    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