Question

我在使用Commander JS和Promise时遇到了麻烦。我正在创建一个CLI工具，该工具执行一些文件系统操作，这些操作包装在Promise中，并且大部分情况下都在起作用。但是，当我通过诺言添加更多文件系统工作时，我注意到该命令将过早终止。我试图通过使用setTimeout调用模拟工作来简化我的示例，以试图找出我感到困惑的地方。这是我用来演示该问题的代码：

var program = require('commander');
fs = require('fs');
path = require('path');


program
    .version('0.0.1')
    .command('add [options] <package.json>', 'Adds Tizen commands line build support to an existing Tizen project.').alias('a')
    .option('-f, --file [package.json]', 'File which contains the package.json project description')
    .option('-c, --config [config]', 'Path to the config.xml where the projectId is read from.')
    .option('-p, --projectid [projectid]', 'The project Id to use in the project.')

    .action(() => {
        console.log('taking action...');
        return new Promise((resolve) => {

                console.log('setting timeout...');

                setTimeout(() => {
                    console.log('Timeout!');
                    resolve();
                } ,2000);

            }
        ).then(() => console.log('Done'));
    })
    .parse(process.argv);

console.log('parse completed...');
console.log('running outer promise...');
return new Promise((resolve) => {

        console.log('setting timeout...');

        setTimeout(() => {
            console.log('Timeout!');
            resolve();
        } ,2000);

    }
).then(() => console.log('Done'));

当我运行它时，我得到：

taking action...
setting timeout...
parse completed...
running outer promise...
setting timeout...

Process finished with exit code 0

但是，当我注释如下的解析调用时，它似乎要等待外部承诺：

    .action(() => {
        console.log('taking action...');
        return new Promise((resolve) => {

                console.log('setting timeout...');

                setTimeout(() => {
                    console.log('Timeout!');
                    resolve();
                } ,2000);

            }
        ).then(() => console.log('Done'));
    })
    //.parse(process.argv);

console.log('parse completed...');
console.log('running outer promise...');
return new Promise((resolve) => {

        console.log('setting timeout...');

        setTimeout(() => {
            console.log('Timeout!');
            resolve();
        } ,2000);

    }
).then(() => console.log('Done'));

我在这里得到：

parse completed...
running outer promise...
setting timeout...
Timeout!
Done

Process finished with exit code 0

就好像对解析的调用在内部触发了某种动作，使动作回调完成后程序就可以完成。如何让它等待实际操作完成？

CommanderJS不等待Promise解决

0 个答案: