需要模块时，squareArea不是函数

Question

I made a set of functions and none of them is working. Here's one of them, for example:

function squareArea(side) {
  var sArea = side * side;
  return sArea;
}

And this is how I require the module:

var mfs = require("m-p-formulas-js");
var test = mfs.squareArea(2);
console.log(test)

It returns this error:

TypeError: mfs.squareArea is not a function

What should I do to solve this?

Answer 1

You aren't exporting the function so it doesn't exist on the require d module object. Assuming you're using ES5, use module.exports which contains the module's exports:

function squareArea(side) {
  var sArea = side * side;
  return sArea;
}
module.exports = {
  squareArea: squareArea
};

You could also shorten it to this using the exports shortcut:

exports.squareArea = squareArea;

Answer 2

You need to export the function to make it available to others. Add the following to the bottom of your definition of mp-formulas-js module:

module.exports = {
    squareArea
}