使用nodejs测试js文件

Question

I try to understand how to test js files. Look, I have a file emotify.js with function:

function emotify(string) {
 return string + '' + ' :)'; 
}

and then I created another file - index.js with the content below:

var emotify = require('./emotify.js');
console.log(emotify('just testing'));

but console push me an error

 TypeError: emotify is not a function

What is wrong ?

Answer 1

When you require a module the result is what the module have exported. In this case you will need to export your function:

emotify.js code:

module.exports = function(string) {
 return string + '' + ' :)'; 
}

Answer 2

Variant 1

emotify.js:

module.exports = function emotify(string) { // Named function, good for call stack at debugging. You are pro, right ?
 return string + '' + ' :)'; 
}

test.js:

const emotify = require('./emotify.js'); // const instead of var, cause you are pro :)
console.log(emotify('just testing'));

Variant 2

mylib.js:

function emotify(string) {
 return string + '' + ' :)'; 
}

function anotherFunc(string) {
 return string + '' + ' :)'; 
}

module.exports = {
 emotify,
 anotherFunc,
};

test.js:

const mylib = require('./mylib.js');

console.log(mylib.emotify('just testing'));
console.log(mylib.anotherFunc('just testing'));

================

Useful links:

• https://nodejs.org/api/modules.html
• https://jestjs.io/