blocks|key|612501|text|同步：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|612502|var+fs+=+require('fs');
var+array+=+fs.readFileSync('file.txt').toString().split("\n");
for(i+in+array)+{
++++console.log(array[i]);
}|code-block|syntax|javascript|612503|异步：|612504|var+fs+=+require('fs');
fs.readFile('file.txt',+function(err,+data)+{
++++if(err)+throw+err;
++++var+array+=+data.toString().split("\n");
++++for(i+in+array)+{
++++++++console.log(array[i]);
++++}
});|612505|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|$]]

<h2>Synchronous:</h2>

<pre><code>var fs = require('fs');
var array = fs.readFileSync('file.txt').toString().split("\n");
for(i in array) {
 console.log(array[i]);
}
</code></pre>

<h2>Asynchronous:</h2>

<pre><code>var fs = require('fs');
fs.readFile('file.txt', function(err, data) {
 if(err) throw err;
 var array = data.toString().split("\n");
 for(i in array) {
 console.log(array[i]);
 }
});
</code></pre>

blocks|key|612600|text|使用Node.js+readline+module。|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|612601|var+fs+=+require('fs');
var+readline+=+require('readline');

var+filename+=+process.argv[2];
readline.createInterface({
++++input:+fs.createReadStream(filename),
++++terminal:+false
}).on('line',+function(line)+{
+++console.log('Line:+'+%2B+line);
});|code-block|syntax|javascript|612602|entityMap|0|LINK|mutability|MUTABLE|url|https://nodejs.org/api/readline.html^0|A|F|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]]]]

Using the Node.js <a href="https://nodejs.org/api/readline.html" rel="noreferrer">readline module</a>.

<pre><code>var fs = require('fs');
var readline = require('readline');

var filename = process.argv[2];
readline.createInterface({
 input: fs.createReadStream(filename),
 terminal: false
}).on('line', function(line) {
 console.log('Line: ' + line);
});
</code></pre>

blocks|key|828244|text|js：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|828245|var+array+=+fs.readFileSync('file.txt',+'utf8').split('\n');|code-block|syntax|javascript|828246|ts：|828247|var+array+=+fs.readFileSync('file.txt',+'utf8').toString().split('\n');|828248|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|$]]

js:

<pre><code>var array = fs.readFileSync('file.txt', 'utf8').split('\n');
</code></pre>

ts:

<pre><code>var array = fs.readFileSync('file.txt', 'utf8').toString().split('\n');
</code></pre>

blocks|key|612827|text|使用readline+(documentation)。下面是一个读取css文件、解析图标并将其写入json的示例|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|612828|var+results+=+[];
++var+rl+=+require('readline').createInterface({
++++input:+require('fs').createReadStream('./assets/stylesheets/_icons.scss')
++});


++//+for+every+new+line,+if+it+matches+the+regex,+add+it+to+an+array
++//+this+is+ugly+regex+:)
++rl.on('line',+function+(line)+{
++++var+re+=+/\.icon-icon.*:/;
++++var+match;
++++if+((match+=+re.exec(line))+!==+null)+{
++++++results.push(match[0].replace(".",'').replace(":",''));
++++}
++});


++//+readline+emits+a+close+event+when+the+file+is+read.
++rl.on('close',+function(){
++++var+outputFilename+=+'./icons.json';
++++fs.writeFile(outputFilename,+JSON.stringify(results,+null,+2),+function(err)+{
++++++++if(err)+{
++++++++++console.log(err);
++++++++}+else+{
++++++++++console.log("JSON+saved+to+"+%2B+outputFilename);
++++++++}
++++});
++});|code-block|syntax|javascript|612829|entityMap|0|LINK|mutability|MUTABLE|url|https://nodejs.org/api/readline.html^0|C|D|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]]]]

use readline (<a href="https://nodejs.org/api/readline.html" rel="noreferrer">documentation</a>). here's an example reading a css file, parsing for icons and writing them to json

<pre><code>var results = [];
 var rl = require('readline').createInterface({
 input: require('fs').createReadStream('./assets/stylesheets/_icons.scss')
 });


 // for every new line, if it matches the regex, add it to an array
 // this is ugly regex :)
 rl.on('line', function (line) {
 var re = /\.icon-icon.*:/;
 var match;
 if ((match = re.exec(line)) !== null) {
 results.push(match[0].replace(".",'').replace(":",''));
 }
 });


 // readline emits a close event when the file is read.
 rl.on('close', function(){
 var outputFilename = './icons.json';
 fs.writeFile(outputFilename, JSON.stringify(results, null, 2), function(err) {
 if(err) {
 console.log(err);
 } else {
 console.log("JSON saved to " + outputFilename);
 }
 });
 });
</code></pre>

blocks|key|828153|text|使用JFile+package的file.lines|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|828154|伪|828155|var+JFile=require('jfile');

var+myF=new+JFile("./data.txt");
myF.lines+//+["first+line","second+line"]+....|code-block|syntax|javascript|828156|之前别忘了：|828157|npm+install+jfile+--save|828158|entityMap|0|LINK|mutability|MUTABLE|url|https://npmjs.org/package/jfile^0|G|A|2|D|0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|Y|8|@$9|Z|A|10|B|C]]|D|@$9|11|A|12|1|13]]|E|$]]|$1|F|3|G|5|6|7|14|8|@]|D|@]|E|$]]|$1|H|3|I|5|J|7|15|8|@]|D|@]|E|$K|L]]|$1|M|3|N|5|6|7|16|8|@]|D|@]|E|$]]|$1|O|3|P|5|J|7|17|8|@]|D|@]|E|$K|L]]|$1|Q|3|-4|5|6|7|18|8|@]|D|@]|E|$]]]|R|$S|$5|T|U|V|E|$W|X]]]]

<code>file.lines</code> with <a href="https://npmjs.org/package/jfile" rel="noreferrer">JFile package</a>
<h1>Pseudo</h1>
<pre><code>var JFile=require('jfile');

var myF=new JFile(&quot;./data.txt&quot;);
myF.lines // [&quot;first line&quot;,&quot;second line&quot;] ....
</code></pre>
Don't forget before :
<pre><code>npm install jfile --save
</code></pre>

blocks|key|612543|text|使用BufferedReader，但该函数应该是异步的：|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|612544|var+load+=+function+(file,+cb){
++++var+lines+=+[];
++++new+BufferedReader+(file,+{+encoding:+"utf8"+})
++++++++.on+("error",+function+(error){
++++++++++++cb+(error,+null);
++++++++})
++++++++.on+("line",+function+(line){
++++++++++++lines.push+(line);
++++++++})
++++++++.on+("end",+function+(){
++++++++++++cb+(null,+lines);
++++++++})
++++++++.read+();
};

load+("file",+function+(error,+lines){
++++if+(error)+return+console.log+(error);
++++console.log+(lines);
});|code-block|syntax|javascript|612545|entityMap|0|LINK|mutability|MUTABLE|url|https://github.com/Gagle/Node-BufferedReader^0|2|E|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]]]]

With a <a href="https://github.com/Gagle/Node-BufferedReader">BufferedReader</a>, but the function should be asynchronous:

<pre><code>var load = function (file, cb){
 var lines = [];
 new BufferedReader (file, { encoding: "utf8" })
 .on ("error", function (error){
 cb (error, null);
 })
 .on ("line", function (line){
 lines.push (line);
 })
 .on ("end", function (){
 cb (null, lines);
 })
 .read ();
};

load ("file", function (error, lines){
 if (error) return console.log (error);
 console.log (lines);
});
</code></pre>

blocks|key|827970|text|这是@mtomis对上面答案的一个变体。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|827971|它创建了一个线流。它发出'data‘和'+end’事件，允许你处理流的结尾。|827972|var+events+=+require('events');

var+LineStream+=+function+(input)+{
++++var+remaining+=+'';

++++input.on('data',+function+(data)+{
++++++++remaining+%2B=+data;
++++++++var+index+=+remaining.indexOf('\n');
++++++++var+last+=+0;
++++++++while+(index+>+-1)+{
++++++++++++var+line+=+remaining.substring(last,+index);
++++++++++++last+=+index+%2B+1;
++++++++++++this.emit('data',+line);
++++++++++++index+=+remaining.indexOf('\n',+last);
++++++++}
++++++++remaining+=+remaining.substring(last);
++++}.bind(this));

++++input.on('end',+function()+{
++++++++if+(remaining.length+>+0)+{
++++++++++++this.emit('data',+remaining);
++++++++}
++++++++this.emit('end');
++++}.bind(this));
}

LineStream.prototype+=+new+events.EventEmitter;|code-block|syntax|javascript|827973|将其用作包装器：|827974|var+lineInput+=+new+LineStream(input);

lineInput.on('data',+function+(line)+{
++++//+handle+line
});

lineInput.on('end',+function()+{
++++//+wrap+it+up
});|827975|entityMap^0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|O|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|P|8|@]|9|@]|A|$]]|$1|D|3|E|5|F|7|Q|8|@]|9|@]|A|$G|H]]|$1|I|3|J|5|6|7|R|8|@]|9|@]|A|$]]|$1|K|3|L|5|F|7|S|8|@]|9|@]|A|$G|H]]|$1|M|3|-4|5|6|7|T|8|@]|9|@]|A|$]]]|N|$]]

This is a variation on the answer above by @mtomis.

It creates a stream of lines. It emits 'data' and 'end' events, allowing you to handle the end of the stream.

<pre><code>var events = require('events');

var LineStream = function (input) {
 var remaining = '';

 input.on('data', function (data) {
 remaining += data;
 var index = remaining.indexOf('\n');
 var last = 0;
 while (index &gt; -1) {
 var line = remaining.substring(last, index);
 last = index + 1;
 this.emit('data', line);
 index = remaining.indexOf('\n', last);
 }
 remaining = remaining.substring(last);
 }.bind(this));

 input.on('end', function() {
 if (remaining.length &gt; 0) {
 this.emit('data', remaining);
 }
 this.emit('end');
 }.bind(this));
}

LineStream.prototype = new events.EventEmitter;
</code></pre>

Use it as a wrapper:

<pre><code>var lineInput = new LineStream(input);

lineInput.on('data', function (line) {
 // handle line
});

lineInput.on('end', function() {
 // wrap it up
});
</code></pre>

blocks|key|828213|text|我只想在异步示例中添加@finbarr的很好的答案，一个小小的修复：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|828214|异步：|828215|var+fs+=+require('fs');
fs.readFile('file.txt',+function(err,+data)+{
++++if(err)+throw+err;
++++var+array+=+data.toString().split("\n");
++++for(i+in+array)+{
++++++++console.log(array[i]);
++++}
++++done();
});|code-block|syntax|javascript|828216|@MadPhysicist，done()是释放异步的方法。打电话。|828217|entityMap^0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|M|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|N|8|@]|9|@]|A|$]]|$1|D|3|E|5|F|7|O|8|@]|9|@]|A|$G|H]]|$1|I|3|J|5|6|7|P|8|@]|9|@]|A|$]]|$1|K|3|-4|5|6|7|Q|8|@]|9|@]|A|$]]]|L|$]]

i just want to add @finbarr great answer, a little fix in the asynchronous example:

Asynchronous:

<pre><code>var fs = require('fs');
fs.readFile('file.txt', function(err, data) {
 if(err) throw err;
 var array = data.toString().split("\n");
 for(i in array) {
 console.log(array[i]);
 }
 done();
});
</code></pre>

@MadPhysicist, done() is what releases the async. call.

blocks|key|612757|text|我也遇到过同样的问题，我已经用模块逐行解决了这个问题。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|612758|https://www.npmjs.com/package/line-by-line|offset|length|612759|至少对我来说，无论是在同步模式还是异步模式下，它的工作方式都很出色。|612760|此外，行终止而不是终止的问题也可以使用以下选项来解决：|612761|{+encoding:+'utf8',+skipEmptyLines:+false+}|code-block|syntax|javascript|612762|行的同步处理：|612763|var+LineByLineReader+=+require('line-by-line'),
++++lr+=+new+LineByLineReader('big_file.txt');

lr.on('error',+function+(err)+{
++++//+'err'+contains+error+object
});

lr.on('line',+function+(line)+{
++++//+'line'+contains+the+current+line+without+the+trailing+newline+character.
});

lr.on('end',+function+()+{
++++//+All+lines+are+read,+file+is+closed+now.
});+|612764|entityMap|0|LINK|mutability|MUTABLE|url^0|0|0|16|0|0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|Z|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|10|8|@]|9|@$D|11|E|12|1|13]]|A|$]]|$1|F|3|G|5|6|7|14|8|@]|9|@]|A|$]]|$1|H|3|I|5|6|7|15|8|@]|9|@]|A|$]]|$1|J|3|K|5|L|7|16|8|@]|9|@]|A|$M|N]]|$1|O|3|P|5|6|7|17|8|@]|9|@]|A|$]]|$1|Q|3|R|5|L|7|18|8|@]|9|@]|A|$M|N]]|$1|S|3|-4|5|6|7|19|8|@]|9|@]|A|$]]]|T|$U|$5|V|W|X|A|$Y|C]]]]

I had the same problem, and I have solved it with the module line-by-line

<a href="https://www.npmjs.com/package/line-by-line" rel="nofollow">https://www.npmjs.com/package/line-by-line</a>

At least for me works like a charm, both in synchronous and asynchronous mode.

Also, the problem with lines terminating not terminating \n can be solved with the option: 

<pre><code>{ encoding: 'utf8', skipEmptyLines: false }
</code></pre>

Synchronous processing of lines:

<pre><code>var LineByLineReader = require('line-by-line'),
 lr = new LineByLineReader('big_file.txt');

lr.on('error', function (err) {
 // 'err' contains error object
});

lr.on('line', function (line) {
 // 'line' contains the current line without the trailing newline character.
});

lr.on('end', function () {
 // All lines are read, file is closed now.
}); 
</code></pre>

blocks|key|612974|text|使用Node.js+v8或更高版本有一个新功能，可以将普通函数转换为异步函数。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|612975|util.promisify|offset|length|612976|这是一个很棒的功能。下面是将txt文件中的10000个数字解析成一个数组，并使用合并排序对这些数字进行倒数计算的示例。|612977|//+read+from+txt+file
const+util+=+require('util');
const+fs+=+require('fs')
fs.readFileAsync+=+util.promisify(fs.readFile);
let+result+=+[]

const+parseTxt+=+async+(csvFile)+=>+{
++let+fields,+obj
++const+data+=+await+fs.readFileAsync(csvFile)
++const+str+=+data.toString()
++const+lines+=+str.split('\r\n')
++//+const+lines+=+str
++console.log("lines",+lines)
++//+console.log("str",+str)

++lines.map(line+=>+{
++++if(!line)+{return+null}
++++result.push(Number(line))
++})
++console.log("result",result)
++return+result
}
parseTxt('./count-inversion.txt').then(()+=>+{
++console.log(mergeSort({arr:+result,+count:+0}))
})|code-block|syntax|javascript|612978|entityMap|0|LINK|mutability|MUTABLE|url|https://nodejs.org/dist/latest-v8.x/docs/api/util.html^0|0|0|E|0|0|0|0^^$0|@$1|2|3|4|5|6|7|U|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|V|8|@]|9|@$D|W|E|X|1|Y]]|A|$]]|$1|F|3|G|5|6|7|Z|8|@]|9|@]|A|$]]|$1|H|3|I|5|J|7|10|8|@]|9|@]|A|$K|L]]|$1|M|3|-4|5|6|7|11|8|@]|9|@]|A|$]]]|N|$O|$5|P|Q|R|A|$S|T]]]]

Using Node.js v8 or later has a new feature that converts normal function into an async function.

<a href="https://nodejs.org/dist/latest-v8.x/docs/api/util.html" rel="nofollow noreferrer">util.promisify</a>

It's an awesome feature. Here's the example of parsing 10000 numbers from the txt file into an array, counting inversions using merge sort on the numbers.

<pre><code>// read from txt file
const util = require('util');
const fs = require('fs')
fs.readFileAsync = util.promisify(fs.readFile);
let result = []

const parseTxt = async (csvFile) =&gt; {
 let fields, obj
 const data = await fs.readFileAsync(csvFile)
 const str = data.toString()
 const lines = str.split('\r\n')
 // const lines = str
 console.log("lines", lines)
 // console.log("str", str)

 lines.map(line =&gt; {
 if(!line) {return null}
 result.push(Number(line))
 })
 console.log("result",result)
 return result
}
parseTxt('./count-inversion.txt').then(() =&gt; {
 console.log(mergeSort({arr: result, count: 0}))
})
</code></pre>

I would like to read a very, very large file into a JavaScript array in node.js.

So, if the file is like this:

<pre><code>first line
two 
three
...
...
</code></pre>

I would have the array: 

<pre><code>['first line','two','three', ... , ... ] 
</code></pre>

The function would look like this:

<pre><code>var array = load(filename); 
</code></pre>

Therefore the idea of loading it all as a string and then splitting it is not acceptable.

node.js: read a text file into an array. (Each line an item in the array.)

JSON

我想在node.js中将一个非常非常大的文件读入一个JavaScript数组。所以，如果文件是这样的：first linetwo three......我会有一个数组：['first line','two','three', ... , ... ] 该函数将如下所示：var array = load(filename); 因此，将其作为字符串加载，然后拆分它的想法是不可接受的。

问node.js:将文本文件读入数组。(数组中的每一行都是一个项目。)
EN

回答 10

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问node.js:将文本文件读入数组。(数组中的每一行都是一个项目。)EN

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问node.js:将文本文件读入数组。(数组中的每一行都是一个项目。)
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