jscoding/lib/io.js

A envirement for coding and debugging javascript language.

import fs from 'fs';
import readline from 'readline';
import hint from './hint';

const options = {
    buffer: null,
    readline: null,
}

/**
 * @method readFromBuffer
 * @param {Number} size 
 * @returns {Promise}
 * @description 从缓冲区逐个读入
 */
function readFromBuffer(size) { // size: 读取的个数
    let buffer = options.buffer;
    return new Promise((resolve) => {
        let arr = [];
        size = size > buffer.length ?
            buffer.length :
            size;
        while (arr.length < size) {
            arr.push(buffer.shift())
        }
        resolve(arr.join('\n')); // 多行数据之间以换行符 '\n' 分隔
    });
}

/**
 * @method readFromReadline
 * @param {Number} size 
 * @returns {Promise}
 * @description  从命令行按行读入
 */
function readFromReadline(size) { // size: 读取的行数
    let readline = options.readline;
    return new Promise((resolve, reject) => {
        let arr = [];
        hint.warn("INPUT: ");
        readline && readline.on('line', (line) => {
            line ||
                readline.close(); // 输入为空时退出程序
            arr.push(line);
            if (arr.length >= size) {
                return resolve(arr.join('\n')); // 多行数据之间以换行符 '\n' 分隔
            }
        });
    });
}

const input = (size = 1) => { // size: 读取的行数，默认取 1 行即返回数据，多行数据之间以换行符 '\n' 分隔
    if (options.buffer) {
        return readFromBuffer(size);
    } else {
        return readFromReadline(size);
    }
}

const output = (msg) => {
    return hint.success("OUTPUT: ", msg);
}

const close = () => {
    options.readline &&
        options.readline.close();
    hint.success("Program closed!");
    process.exit(0);
}

const initialize = (config = null) => {

    if (!(config.buffer || config.file)) {
        options.readline = readline.createInterface({
            input: process.stdin,
            prompt: "> ", // 设置每当调用 rl.prompt() 时将写入 output 的提示。
        });
        options.readline.on('close', () => {
            hint.success("Program closed!");
            process.exit(0); // readline 关闭时即退出程序
        });
    } else if (config && config.buffer && Array.isArray(config.buffer)) {
        options.buffer = config.buffer;
    } else if (config && config.filename && typeof config.filename == 'string') {
        if (fs.statSync(config.filename).isFile()) {
            options.buffer = fs.readFileSync(config.filename)
                .toString()
                .split(/ *\r*\n/ig);
        } else {
            hint.error("The input isn't a file!");
        }
    } else { /* To do something */ }

    return true;
}

export {
    initialize as init,
    input as readline,
    output as print,
    close,
}