我正在尝试编写一个 Markdown 预处理器,它可以在输出中包含其他文件。
不幸的是,我发现"the pause method does not stop queued up line events" .
我编写的解决方案将完成原始文件的读取和写入,然后在最后附加其他文件:
import { createInterface } from "readline";
import * as fs from "fs";
import * as path from "path";
import minimist from "minimist";
const argv = minimist(process.argv.slice(2));
const inputFile = path.resolve(argv._[0]);
const outputFile = path.resolve(argv._[1]);
const inputFileReadStream = createInterface({
"input": fs.createReadStream(inputFile)
});
const writeStream = fs.createWriteStream(outputFile);
readStream.on("line", function readLine(line) {
if (line.startsWith("@import") === true) {
inputFileReadStream.pause();
console.log(line.substring(line.indexOf("\"") + 1, line.lastIndexOf("\"")));
const readStream = createInterface({
"input": fs.createReadStream(path.resolve(path.dirname(inputFile), line.substring(line.indexOf("\"") + 1, line.lastIndexOf("\""))))
});
readStream.on("line", function(line) {
readLine(line);
});
readStream.on("end", function() {
inputFileReadStream.resume();
});
} else {
writeStream.write(line + "\n");
}
});
所以我尝试修改它以使用 line-by-line
我链接的帖子中提到的库,看看这是否有效:
let readStream = new (require("line-by-line"))(fs.createReadStream(inputFile));
const writeStream = fs.createWriteStream(outputFile);
readStream.on("line", function readLine(line) {
if (line.startsWith("@import") === true) {
const tempStream = readStream;
tempStream.pause();
console.log(line.substring(line.indexOf("\"") + 1, line.lastIndexOf("\"")));
readStream = new (require("line-by-line"))(fs.createReadStream(path.resolve(path.dirname(inputFile), line.substring(line.indexOf("\"") + 1, line.lastIndexOf("\"")))));
readStream.on("line", function(line) {
readLine(line);
});
readStream.on("end", function() {
tempStream.resume();
});
} else {
writeStream.write(line + "\n");
}
});
但这生成了一个文件,该文件逐渐将导入文件中的行散布到主文件中。
我的问题是:有没有办法让 readline
正确响应 pause
事件?
这可以用 Transform
来修复吗? ?
如果有帮助,这里是存储库的链接:https://github.com/brianjenkins94/Rosettas-Node
这可能会对性能产生负面影响,但我通过将 highWaterMark
值设置为 1
得到了我想要的结果。
import { createInterface } from "readline";
import * as fs from "fs";
import * as path from "path";
import minimist from "minimist";
const argv = minimist(process.argv.slice(2));
const inputFile = path.resolve(argv._[0]);
const outputFile = path.resolve(argv._[1]);
const inputFileReadStream = createInterface({
"input": fs.createReadStream(inputFile, { "highWaterMark": 1 })
});
const writeStream = fs.createWriteStream(outputFile);
inputFileReadStream.on("line", function readLine(line, readStream = inputFileReadStream) {
if (line.startsWith("@import") === true) {
readStream.pause();
const childReadStream = createInterface({
"input": fs.createReadStream(path.resolve(path.dirname(inputFile), line.substring(line.indexOf("\"") + 1, line.lastIndexOf("\""))), { "highWaterMark": 1 })
});
childReadStream.on("line", function(line) {
readLine(line, childReadStream);
});
childReadStream.on("close", function() {
readStream.resume();
});
} else {
writeStream.write(line + "\n");
}
});
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