javascript - 为什么 Node 只是打印出文件中的内容？

Question

我对 node.js 有疑问，我对它不是很熟悉。

我有一个 JavaScript 文件，我需要使用 .load "filename.js" 将该文件加载到 node.js。

当我运行命令时，我只打印了文件中的代码。

这是我要加载的文件的代码。我已经进行了向我建议的更改。但我仍然从代码中得到完整的打印结果。

class ArithmeticTaskRunner 
{
  constructor()
  {
    this.tasks = [];
  }
  addNegationTask()
  {
    const negationTask = (x) => -x;
    this.tasks.push(negationTask)
    return this;
  }
  addAdditionTask(y)
  {
    const additionByY = (x) => x + y;
    this.tasks.push(additionByY)
    return this;
  }
  addMultiplicationTask(y)
  {
    const multiplyByY = (x) => x * y;
    this.tasks.push(multiplyByY)
    return this;
  }
  taskCount()
  {
    return this.tasks.length;
  }
  execute(n)
  {
    let currentResult = n;
    for(let task of this.tasks)
    {
        currentResult = task(currentResult)
    }
    return currentResult;
  }
}
let taskRunner = new ArithmeticTaskRunner()
taskRunner.addAdditionTask(10)
taskRunner.addNegationTask()
taskRunner.addMultiplicationTask() 
taskRunner.execute(2)

这里是这个任务需要的输出和输入的例子

1.

let taskRunner = new ArithmeticTaskRunner() undefined taskRunner.addAdditionTask(2) undefined taskRunner.addMultiplicationTask(4) undefined taskRunner.addAdditionTask(10) undefined taskRunner.execute(2) 26 taskRunner.execute(-2) 10

2.

taskRunner.execute() -5 taskRunner.execute(10) -10 taskRunner.taskCount 3

Answer 1

如果你想有一个 REPL session 并在命令行中运行命令，你可以使用 repl 模块。

const repl = require('repl');

class ArithmeticTaskRunner {
  ... // Your class definition
}

// This starts the REPL session with the ArithmeticTaskRunner defined
repl.start().context.ArithmeticTaskRunner = ArithmeticTaskRunner;

然后在终端:

node filename.js

当你有 Node 运行时:

let taskRunner = new ArithmeticTaskRunner()
taskRunner.addAdditionTask(2)
taskRunner.addMultiplicationTask(4)
taskRunner.addAdditionTask(10)
taskRunner.execute(2)
taskRunner.execute(-2)

如果要完整运行代码并输出结果，请在代码中使用console.log 并运行node filename.js:

class ArithmeticTaskRunner {
  ... // Your class definition
}

let taskRunner = new ArithmeticTaskRunner()
taskRunner.addAdditionTask(2)
taskRunner.addMultiplicationTask(4)
taskRunner.addAdditionTask(10)

console.log(taskRunner.execute(2))
console.log(taskRunner.execute(-2))

在终端中:

node filename.js