如何检查文件中的一行是否存在于 Javascript 中的文件中？

Question

我是 javascript 新手，我想检查一个文件的行是否存在于另一个文件中。我有以下代码：

async getReadLiner(filename) {
    const fileStream = fs.createReadStream(filename);
    const rl = readline.createInterface({
      input: fileStream,
    });
    return rl;
}

有没有可能做类似的事情

checkLines() {
    const file1 = await this.getReadLiner(filename1);
    const file2 = await this.getReadLiner(filename2);
    for await (const line of file1) {
      for await (const file2Line of file2) { 
            if (file2Line == line) // It's not executing this line at all.
                return true;
        }
    }
    return false
}

知道为什么这条线（if (file2Line == line) 没有执行吗？

提前致谢。

Answer 1

有没有可能做类似的事情

是的，readline 模块的文档中有一个example of that，如下所示：

const fs = require('fs');
const readline = require('readline');

async function processLineByLine() {
  const fileStream = fs.createReadStream('input.txt');

  const rl = readline.createInterface({
    input: fileStream,
    crlfDelay: Infinity
  });
  // Note: we use the crlfDelay option to recognize all instances of CR LF
  // ('\r\n') in input.txt as a single line break.

  for await (const line of rl) {
    // Each line in input.txt will be successively available here as `line`.
    console.log(`Line from file: ${line}`);
  }
}

processLineByLine();

调整循环：

const targetLine = "helo 123";
for await (const line of getReadLiner(/*...*/)) {
    if (line === targetLine) { // Or line.includes(targetLine) for a substring match
        // Found it
        break;
    }
}