使用 Node.js 暂停控制台输出

Question

I am trying to create a time display (h:mm:ss) with just using the console and not on a web page. The time should be set initially and from there display the time as it changes.

When using the output console (in the web browser) or in vscode, is it possible for js or node.js, while printing thousands/multiple outputs to have a delay between each output being printed in the console without using an extension?

Answer 1

Here's an example of printing the current time to the console every 1 second:

 // setInterval() executes the given function on a given time interval setInterval(() => { console.log(new Date().toTimeString()); // function to execute }, 1000) // execute every 1000 ms

You can also print your own counter:

 let secondsElapsed = 0 setInterval(() => { console.log(`seconds elapsed = ${secondsElapsed}`); secondsElapsed++; }, 1000)

Answer 2

Here is how to accomplish what you seem to be asking:

 const clockTick = (callback) => { const tick = () => { const now = Date.now(); callback(now); setTimeout(tick, 1000 - (now % 1000)); } tick(); } clockTick(timestamp => { const date = new Date(timestamp); const hours = date.getHours(); const minutes = date.getMinutes(); const seconds = date.getSeconds(); console.log(`${hours}:${minutes}:${seconds}`); });

Answer 3

The accepted answer isn't correct. IMO, we should implement a queue or something similar in order to achieve "delay between each output". I find this question interesting so I implement this code for some fun (which use promise chain as a simple queue):

const callNext = (function () {
  let queueChain = Promise.resolve();

  // Called after previous command (1 second by default)
  function callNext(func, delay = 1000) {
    queueChain = queueChain.then(() => {
      return new Promise((res) => {
        setTimeout(() => {
          func();
          res();
        }, delay);
      });
    });
  }

  return callNext;
})();

callNext(() => {
  console.log('run after 3s')
}, 3000);

callNext(() => {
  console.log('run after the above 3s')
}, 3000);

callNext(() => {
  console.log('run after the above 1s by default')
});

we can create a simple logger using the above callNext for cleaner syntax:

const logger = (function () {
  function createLogFn(name) {
    return function (...args) {
      let delay = 1000;

      // take the last argument as "delay" param
      if (typeof args[args.length -1] === 'number') {
        delay = args.pop();
      }

      callNext(() => {
        console[name](`${name.toUpperCase()} [${(new Date().toISOString())}]: `, ...args);
      }, delay);
    };
  }

  const logger = {
    log: createLogFn('log'),
    info: createLogFn('info'),
    debug: createLogFn('debug'),
    error: createLogFn('error'),
  }
  return logger;
})();

logger.log('run after 3s', 3000);
logger.log('run after the above 3s', 3000);
logger.log('run after the above 1s');

logger.info('final run after the above 2s', 2000);

Check it out: https://jsfiddle.net/pk5oqfxa/