Viscerally / 2018-05-11_Modules-and-Testing

Modules and Testing

Modules

What is a module and what problem does it solve?

• Module is a JavaScript file that we cann use in another JavaScript file

• theres some on thev internet

• modules are accessed through js objects

• organize

• responsibility and architechture

• reusability

require accepts a file path as its input and returns the exports object from that file;

Node puts all code in a file within a function that looks like (function (exports, require, module, __filename, __dirname) { This means that:

• all vars in node file are local to that file
• function params can be unique to each function, so every file gets its own version of exports, require, module, __filename, __dirname.

npm

• manages node packages
• Every project should have its own package.json
• create a package.json using npm init

mocha

mocha is a BDD style test framework for node. it allows us to write unit tests.

• install using npm install --save-dev mocha
• run tests using ./node_modules/mocha/bin/mocha

Links

https://www.npmjs.com/package/left-pad https://mochajs.org/

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Snippets

// (function (exports, require, module, __filename, __dirname) { 

// all code

// })();

// all vars in node file are local tio that file
// sepasrate
// function partams acan be unique to each function

var yes = hasTime();
var functionHasTime = hasTime;

functionHasTime();