W1D5

basicMath.js

function isValidArray(array) {
    return array.length > 0;
}

function add(numbers) {
    if (isValidArray(numbers)) {
        var result = 0;
        for (var i = 0; i < numbers.length; i++) {
            result = result + numbers[i];
        }

        return result;
    }
    else {
        throw new Error('Input is invalid');
    }
}

function multiply(numbers) {
    if (isValidArray(numbers)) {
        var result = 1;
        for (var i = 0; i < numbers.length; i++) {
            result = result * numbers[i];
        }

        return result;
    }
    else {
        throw new Error('Input is invalid');
    }
}

module.exports = {
    add: add,
    multiply: multiply
};

package.json

{
  "name": "w1d5",
  "version": "1.0.0",
  "description": "",
  "main": "basicMath.js",
  "scripts": {
    "test": "echo \"Error: no test specified\" && exit 1"
  },
  "author": "",
  "license": "ISC",
  "dependencies": {
    "left-pad": "^1.2.0"
  },
  "devDependencies": {
    "assert": "^1.4.1"
  }
}

run.js

var leftPad = require('left-pad');
var basicMath = require('./basicMath');

var testArray = [1, 2, 8];

console.log('add: ', basicMath.add(testArray));
console.log('multiply: ', basicMath.multiply(testArray));

console.log('---With leftPad---');

console.log(leftPad('add: ', 10, ' '), basicMath.add(testArray));
console.log(leftPad('multiply: ', 10, ' '), basicMath.multiply(testArray));

test.js

var basicMath = require('./basicMath');
var assert = require('assert');

describe('add()', function () {
    it('should throw error if no numbers are given', function () {
        assert(basicMath.add, Error, 'Input is invalid');
    });

    it('should return the result of adding the input numbers', function () {
        var result = basicMath.add([1, 2, 3]);
        assert.equal(result, 6);
    });

    it('should return the result of adding the input numbers', function () {
        var result = basicMath.add([3, 5]);
        assert.equal(result, 8);
    });
});

describe('multiply()', function () {
    it('should throw error if no numbers are given', function () {
        assert(basicMath.multiply, Error, 'Input is invalid');
    });

    it('should return the result of multiplying the input numbers', function () {
        var result = basicMath.multiply([1, 2, 3]);
        assert.equal(result, 6);
    });

    it('should return the result of multiplying the input numbers', function () {
        var result = basicMath.multiply([3, 5]);
        assert.equal(result, 15);
    });
});

W1D5 outline.md

Background

1. Objects: collection of key-value pairs, where keys are unique
2. Functions: they're contracts, they take in inputs, they usually output some value
3. Modules: collection of objects and functions that is "exported" and can be "imported"
4. Packages: description of one or more modules that are available to a developer

Modules

1. Modules are not special
2. module.exports
3. Importing modules

npm

1. Collection of packages
2. package.json
3. npm init
4. npm install & npm install -g & npm install --production
5. npm install --save & npm install --save-dev

Testing

1. Installing Mocha
2. describe
3. it
4. assert