Question

如何在调用WriteStream.write()时将数据写入文件？

编辑：事实证明，当我使用REPL并调用函数时，这是有效的。但是，这在我的程序中不起作用：

import * as FS from "fs";
import { LetterGroup } from "./LetterGroup";
import { Dictionary } from "./Dictionary";
import { Word } from "./Word";
import * as OS from "os";

const groups: Array<LetterGroup> = LetterGroup.letterGroupsFromString(FS.readFileSync("./letterGroups.txt").toString());
const dictionary = Dictionary.create(FS.readFileSync("./dictionary.txt").toString());

const inputStr: string = FS.readFileSync("./input.txt").toString();
const inputWords = new Array<Word>();
const fileStream = FS.createWriteStream("./output.txt");

for (const line of inputStr.trim().split(OS.EOL))
{
    inputWords.push(new Word(line));
}

function permute(index: number)
{
    index = Math.floor(index);

    if (!(index >= 0 && index < inputWords.length))
    {
        return;
    }

    const word: Word = inputWords[index];

    let outputString: string = "";

    outputString += `Valid permutations of '${word.wordString}':` + OS.EOL;

    console.log(`Testing '${ word.wordString }'...`);

    for (const permutation of word.generatePermutations(groups, dictionary, true))
    {
        outputString += permutation.wordString + OS.EOL;
    }

    outputString += OS.EOL;
    console.log();

    if (!fileStream.write(outputString))
    {
        console.log("Wrote to file too fast! Will resume writing once the system catches up...");
        fileStream.once("drain", () => permute(index));
        return;
    }

    permute(index + 1);
}

permute(0);

应该注意word.generatePermutations是一种非常密集的功能，通常需要几分钟（有时超过一小时）才能返回。我的问题是它返回的数据应该立即写入输出文件，这样整个程序就不需要完成运行才能读取结果。希望有人能理解这一切。

为了澄清，写入REPL中WriteStream的数据会立即写入文件，而在整个程序运行完毕之前，我的程序中没有数据写入文件。

Answer 1

试试这些套餐：

https://www.npmjs.com/package/flushwritable

https://www.npmjs.com/package/flush-write-stream

我认为你的问题是重复的 How to flush Node.js file writeStream properly?

Node.js WriteStream在关闭之前不会将数据写入文件

1 个答案: