检查argv是否以.js结尾

Question

我正在尝试做一个简单的程序，从命令行侦听argv，但是我得到了这个错误

C:\Users\user\Desktop\RLC Tracker & Updater\obfuscate.js:19
    console.log(name.substr(-3));
                     ^
TypeError: name.substr is not a function
    at Object.<anonymous> (C:\Users\user\Desktop\RLC Tracker & Updater\obfuscate
.js:19:22)
    at Module._compile (internal/modules/cjs/loader.js:689:30)
    at Object.Module._extensions..js (internal/modules/cjs/loader.js:700:10)
    at Module.load (internal/modules/cjs/loader.js:599:32)
    at tryModuleLoad (internal/modules/cjs/loader.js:538:12)
    at Function.Module._load (internal/modules/cjs/loader.js:530:3)
    at Function.Module.runMain (internal/modules/cjs/loader.js:742:12)
    at startup (internal/bootstrap/node.js:266:19)
    at bootstrapNodeJSCore (internal/bootstrap/node.js:596:3)

这是密码

// Select the file as a argv
var name = process.argv.slice(2);

// Checks if the argv is null or empty
if(name == "")
{
    console.log("\nPlease insert the file name.");
}
else if(name.substr(-3) == ".js")
{
    // Code
}
else
{
    //Code
}

Answer 1

.slice()返回一个数组。所以：

var name = process.argv.slice(2);

将name设置为以索引2开头的所有参数的数组。

var name = process.argv[2];

Answer 2

Array.slice()返回一个数组。所以你想说些类似的话：

const name = process.argv.slice(2)[0]; // /will be undefined if not provided
if (!name) {
  console.log("\nPlease insert the file name.");
} else if ( /[.][Jj][Ss]/.test(name) ) {
  // name ends with '.js' (or '.JS' or '.Js' or '.jS')
} else {
  // name does not end with '.js'
}