blocks|key|291860|text|尝试在控制台上使用process.stdout方法：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|291861|process.stdout.write("Hello,+World");
process.stdout.clearLine();
process.stdout.cursorTo(0);
process.stdout.write("\n");+//+end+the+line|code-block|syntax|javascript|291862|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

Try playing with process.stdout methods instead on console:

<pre><code>process.stdout.write("Hello, World");
process.stdout.clearLine();
process.stdout.cursorTo(0);
process.stdout.write("\n"); // end the line
</code></pre>

blocks|key|291890|text|按照@michelek的回答，您可以使用如下所示的函数：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|291891|function+printProgress(progress){
++++process.stdout.clearLine();
++++process.stdout.cursorTo(0);
++++process.stdout.write(progress+%2B+'%25');
}|code-block|syntax|javascript|291892|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

Following @michelek's answer, you can use a function somewhat like this:

<pre><code>function printProgress(progress){
 process.stdout.clearLine();
 process.stdout.cursorTo(0);
 process.stdout.write(progress + '%');
}
</code></pre>

blocks|key|74560|text|当然，您可以使用我帮助创建的一个模块来完成此操作：fknsrs/jetty|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|74561|安装方式|74562|npm+install+jetty|code-block|syntax|javascript|74563|下面是一个用法示例|74564|//+Yeah,+Jetty!
var+Jetty+=+require("jetty");

//+Create+a+new+Jetty+object.+This+is+a+through+stream+with+some+additional
//+methods+on+it.+Additionally,+connect+it+to+process.stdout
var+jetty+=+new+Jetty(process.stdout);

//+Clear+the+screen
jetty.clear();

//+write+something
jetty.text("hello+world");
jetty.moveTo([0,0]);
jetty.text("hello+panda");|74565|Jetty在单独使用时并不是特别有用。当您在其上构建一些抽象以使您的jetty调用不那么冗长时，它会更有效。|74566|entityMap|0|LINK|mutability|MUTABLE|url|https://github.com/fknsrs/jetty^0|P|C|0|0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|Y|8|@]|9|@$A|Z|B|10|1|11]]|C|$]]|$1|D|3|E|5|6|7|12|8|@]|9|@]|C|$]]|$1|F|3|G|5|H|7|13|8|@]|9|@]|C|$I|J]]|$1|K|3|L|5|6|7|14|8|@]|9|@]|C|$]]|$1|M|3|N|5|H|7|15|8|@]|9|@]|C|$I|J]]|$1|O|3|P|5|6|7|16|8|@]|9|@]|C|$]]|$1|Q|3|-4|5|6|7|17|8|@]|9|@]|C|$]]]|R|$S|$5|T|U|V|C|$W|X]]]]

Sure, you can do this using a module I helped create: <a href="https://github.com/fknsrs/jetty" rel="noreferrer">fknsrs/jetty</a>
Install via
<pre><code>npm install jetty
</code></pre>
Here's a usage example
<pre><code>// Yeah, Jetty!
var Jetty = require(&quot;jetty&quot;);

// Create a new Jetty object. This is a through stream with some additional
// methods on it. Additionally, connect it to process.stdout
var jetty = new Jetty(process.stdout);

// Clear the screen
jetty.clear();

// write something
jetty.text(&quot;hello world&quot;);
jetty.moveTo([0,0]);
jetty.text(&quot;hello panda&quot;);
</code></pre>
Jetty is not super useful when used on it's own. It is much more effective when you build some abstraction on top of it to make your jetty calls less verbose.

blocks|key|74671|text|只需使用\r来终止您的线路：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|74672|process.stdout.write('text\r');|code-block|syntax|javascript|74673|这里有一个简单的例子(挂钟)：|74674|setInterval(()+=>+process.stdout.write(`clock:+${new+Date()}\r`),+1000);|74675|entityMap^0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|M|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|N|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|O|8|@]|9|@]|A|$]]|$1|I|3|J|5|D|7|P|8|@]|9|@]|A|$E|F]]|$1|K|3|-4|5|6|7|Q|8|@]|9|@]|A|$]]]|L|$]]

Just use \r to terminate your line:

<pre><code>process.stdout.write('text\r');
</code></pre>

Here's a simple example (wall clock):

<pre><code>setInterval(() =&gt; process.stdout.write(`clock: ${new Date()}\r`), 1000);
</code></pre>

blocks|key|291828|text|若要编写部分行，请执行以下操作。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|291829|process.stdout.write('text');
process.stdout.write('more');
process.stdout.write('\n');+//+end+the+line|code-block|syntax|javascript|291830|如果输出量是真正的问题，那么你可能会重新考虑你的日志。您可以使用允许选择性运行时日志记录的日志记录系统，以将输出范围缩小到您需要的范围。|291831|//+The+sections+we+want+to+log+and+the+minimum+level
var+LOG_LEVEL+=+4;
var+LOG_SECTIONS+=+['section1',+'section2',+'section3'];

function+logit(msg,+section,+level)+{
++if+(LOG_SECTIONS.includes(section)+&&+LOG_LEVEL+>=+level)+{
++++console.log(section+%2B+':'+%2B+msg);
++}
}

logit('message+1',+'section1',+4);+//+will+log
logit('message+2',+'section2',+4);+//+will+log
logit('message+3',+'section3',+2);+//+wont+log,+below+log+level
logit('message+4',+'section4',+4);+//+wont+log,+not+in+a+log+section|291832|entityMap^0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|M|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|N|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|O|8|@]|9|@]|A|$]]|$1|I|3|J|5|D|7|P|8|@]|9|@]|A|$E|F]]|$1|K|3|-4|5|6|7|Q|8|@]|9|@]|A|$]]]|L|$]]

To write a partial line.
<pre class="lang-js prettyprint-override"><code>process.stdout.write('text');
process.stdout.write('more');
process.stdout.write('\n'); // end the line
</code></pre>
If the volume of output is the real issue then you'll probably to rethink your logging. You could use a logging system that allows selective runtime logging to narrow your output to what you need.
<pre class="lang-js prettyprint-override"><code>// The sections we want to log and the minimum level
var LOG_LEVEL = 4;
var LOG_SECTIONS = ['section1', 'section2', 'section3'];

function logit(msg, section, level) {
 if (LOG_SECTIONS.includes(section) &amp;&amp; LOG_LEVEL &gt;= level) {
 console.log(section + ':' + msg);
 }
}

logit('message 1', 'section1', 4); // will log
logit('message 2', 'section2', 4); // will log
logit('message 3', 'section3', 2); // wont log, below log level
logit('message 4', 'section4', 4); // wont log, not in a log section
</code></pre>

blocks|key|74650|text|如果您在Visual+Studio+Code+(或Webstorm)的调试控制台窗口中看到像TypeError:+process.stdout.clearLine+is+not+a+function这样的标准输出异常，请将应用程序作为外部终端应用程序运行，而不是内部控制台。原因是调试控制台窗口不是TTY+(process.stdout.isTTY为false)。因此，使用"console":+"externalTerminal"选项在launch.json中更新您的启动配置。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|74651|entityMap^0|1A|1H|4A|K|57|T|63|B|0^^$0|@$1|2|3|4|5|6|7|H|8|@$9|I|A|J|B|C]|$9|K|A|L|B|C]|$9|M|A|N|B|C]|$9|O|A|P|B|C]]|D|@]|E|$]]|$1|F|3|-4|5|6|7|Q|8|@]|D|@]|E|$]]]|G|$]]

if you see stdout exceptions like <code>TypeError: process.stdout.clearLine is not a function</code> in Debug Console window of Visual Studio Code (or Webstorm), run the app as external terminal application instead of internal console. The reason is that Debug Console window is not TTY (<code>process.stdout.isTTY</code> is false). Therefore update your launch configuration in <code>launch.json</code> with <code>"console": "externalTerminal"</code> option.

blocks|key|74691|text|我们可以使用log-update|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|74692|const+logUpdate+=+require('log-update');
logUpdate('this+will+be+gone');
logUpdate('this+will+stay');|code-block|syntax|javascript|74693|entityMap|0|LINK|mutability|MUTABLE|url|https://www.npmjs.com/package/log-update^0|6|A|0|0|0^^$0|@$1|2|3|4|5|6|7|Q|8|@]|9|@$A|R|B|S|1|T]]|C|$]]|$1|D|3|E|5|F|7|U|8|@]|9|@]|C|$G|H]]|$1|I|3|-4|5|6|7|V|8|@]|9|@]|C|$]]]|J|$K|$5|L|M|N|C|$O|P]]]]

We can use <a href="https://www.npmjs.com/package/log-update" rel="nofollow noreferrer">log-update</a>
<pre><code>const logUpdate = require('log-update');
logUpdate('this will be gone');
logUpdate('this will stay');
</code></pre>

blocks|key|74724|text|其中，@michelek的答案做到了这一点。然而，当你开始使用它时，当输出被重定向到文件，或者你在调试器中，或者在linux屏幕会话中运行时，你可能会遇到异常问题。你可能会看到像process.stdout.clearLine+is+not+a+function这样的消息。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|74725|因此，至少添加一个测试来检查输出是否为'TTY‘，并且能够执行'clearLine()’和‘cursorTo()’这样的操作：|74726|if+(process.stdout.isTTY)+{
+++process.stdout.write("Hello,+World");
+++process.stdout.clearLine(0);
+++process.stdout.cursorTo(0);
+++process.stdout.write("\n");+//+end+the+line
}|code-block|syntax|javascript|74727|entityMap^0|2H|16|0|0|0^^$0|@$1|2|3|4|5|6|7|O|8|@$9|P|A|Q|B|C]]|D|@]|E|$]]|$1|F|3|G|5|6|7|R|8|@]|D|@]|E|$]]|$1|H|3|I|5|J|7|S|8|@]|D|@]|E|$K|L]]|$1|M|3|-4|5|6|7|T|8|@]|D|@]|E|$]]]|N|$]]

Among others, the answer by @michelek does the trick. However, when you start using this, you may run into Exception trouble when output gets redirected to a file or you are in a debugger or running in a linux screen-session, etc. You may see messages such as <code>process.stdout.clearLine is not a function</code>.
Therefore, at least add a test to check that the output is a 'TTY' and is able to do such things as 'clearLine()' and 'cursorTo()':
<pre class="lang-js prettyprint-override"><code>if (process.stdout.isTTY) {
 process.stdout.write(&quot;Hello, World&quot;);
 process.stdout.clearLine(0);
 process.stdout.cursorTo(0);
 process.stdout.write(&quot;\n&quot;); // end the line
}
</code></pre>

My <code>node.js</code> application has a lot of console logs, which are important for me to see (it's quite a big app so runs for a long time and I need to know that things are still progressing) but I'm ending up with thousands of lines of console logs.

Is it somehow possible to do a <code>console.update</code> that erases/replaces a console line rather than creating a new line?

Node.js console.log - Is it possible to update a line rather than create a new line?

Visual Studio

调试器

我的node.js应用程序有很多控制台日志，这对我来说很重要(它是一个很大的应用程序，运行了很长一段时间，我需要知道事情还在进行中)，但我最终得到了数千行控制台日志。有没有可能执行一个console.update来擦除/替换控制台行，而不是创建一个新行？

问Node.js console.log -是否可以更新线路而不是创建新线路？
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回答 8

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问Node.js console.log -是否可以更新线路而不是创建新线路？EN

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问Node.js console.log -是否可以更新线路而不是创建新线路？
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