Javascript Node.js 需要带有构造函数参数的类
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Node.js require class with constructor parameter
提问by MyMomSaysIamSpecial
I have a class
我有一堂课
class advertHandler {
constructor(projects) {
this.projects = projects;
}
getProject(name) {
return this.projects[name];
}
}
module.exports = new advertHandler(projects);
When I try to use it like this
当我尝试像这样使用它时
const advertHandler = require('./advertHandler')(projectsArray);
advertHandler.getProject('test');
And it throws an exception, require is not a function, but without a constructor, everything is fine, so the question is how to use the class constructor with require?
并且它抛出一个异常，require is not a function但是没有构造函数，一切都很好，所以问题是如何使用带有 require 的类构造函数？
回答by T.J. Crowder
It's not saying requireis not a function, it's saying require(...)is not a function. :-) You're trying to callthe result of require(...), but what you're exporting (an instance of advertHandler) isn't a function. Also note that in advertHandler.js, you're trying to use a global called projects(on the last line); ideally, best to to have globals in NodeJS apps when you can avoid it.
不是说require不是函数，而是说require(...)不是函数。:-) 您正在尝试调用的结果require(...)，但是您导出的（ 的实例advertHandler）不是函数。另请注意，在 中advertHandler.js，您正在尝试使用全局调用projects（在最后一行）；理想情况下，最好在可以避免的情况下在 NodeJS 应用程序中使用全局变量。
You just want to export the class:
您只想导出类：
module.exports = advertHandler;
...and then probably require it before calling it:
...然后在调用它之前可能需要它：
const advertHandler = require('./advertHandler');
const handler = new advertHandler({test: "one"});
console.log(handler.getProject('test'));
E.g.:
例如：
advertHandler.js:
advertHandler.js：
class advertHandler {
constructor(projects) {
this.projects = projects;
}
getProject(name) {
return this.projects[name];
}
}
module.exports = advertHandler;
app.js:
应用程序.js：
const advertHandler = require('./advertHandler');
const handler = new advertHandler({test: "one"});
console.log(handler.getProject('test'));
