在用 Nodejs 写 CLI 应用或者做OJ的时候经常会遇到要从 stdin 读取输入的情况，这里总结了几种不依赖第三方库来按行读取输入的方法。
Readline基础使用
- 优点：简洁方便，平台无关。可用于编写 REPL 应用。
- 缺点：某些 OJ 的 node 版本可能不支持readline，对此请参考OJ专用的方法。
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| require("readline")
.createInterface({
input: process.stdin,
output: process.stdout,
})
.on("line", function (line) {
console.log("the input is: ", line.trim());
this.close();
});
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实现互动问答
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| const rl = require("readline").createInterface({
input: process.stdin,
output: process.stdout,
});
const wait = (ms) => new Promise((resolve) => setTimeout(resolve, ms));
const question = (query) =>
new Promise((resolve) => rl.question(query, (answer) => resolve(answer)));
(async () => {
let answer = await question("你觉得node是最棒的吗？ ");
console.log(`您的答案是：${answer}`);
answer = await question("async/await好不好用啊 ");
console.log(`您的答案是：${answer}`);
answer = await question("等待多少秒继续执行？ ");
rl.pause();
await wait(parseInt(answer) * 1000);
rl.resume();
while ((await question("输入bye退出 ")).trim() !== "bye");
console.log("Good day.");
rl.close();
})();
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process.stdin
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| process.stdin.setEncoding("utf8");
process.stdin.on("readable", () => {
var chunk = process.stdin.read();
if (typeof chunk === "string") {
chunk = chunk.slice(0, -1);
process.stdout.write(`stringLength:${chunk.length}\n`);
}
if (chunk === "") {
process.stdin.emit("end");
return;
}
if (chunk !== null) {
process.stdout.write(`data: ${chunk}\n`);
}
});
process.stdin.on("end", () => {
process.stdout.write("end");
});
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