TypeError：无法在module.exports中设置undefined的属性

Question

'use strict';
module.exports = function () {
    this.myVar = 'example';
    console.log(this.myVar);
};

I get the error:

/home/karl/mymodule.js:3
    this.myVar = 'example';
               ^

TypeError: Cannot set property 'myVar' of undefined

Answer 1

In strict mode this is undefined . But in non-strict mode this is nothing but pointing to GLOBAL . So here you are trying to set something to undefined .

Where exactly were you intending to attach myVar ? On your module ? Or on GLOBAL ? If it's on GLOBAL (which is actually a bad idea), use GLOBAL.myVar or global.myVar . If it's on your module you could do module.exports.myVar = 'example';