• 设为首页
  • 点击收藏
  • 手机版
    手机扫一扫访问
    迪恩网络手机版
  • 关注官方公众号
    微信扫一扫关注
    迪恩网络公众号

MartinChavez/Javascript: Javascript : Test-Driven Learning

原作者: [db:作者] 来自: 网络 收藏 邀请

开源软件名称:

MartinChavez/Javascript

开源软件地址:

https://github.com/MartinChavez/Javascript

开源编程语言:

JavaScript 100.0%

开源软件介绍:

Javascript : Test-Driven Learning

This project is aimed to help the user further study Javascript with a test-driven approach. Each unit contains an annotated tutorial and a platform where you can test your understanding of the topic.

Topics

  • Arrays
  • Bad Practices and Solutions
  • Booleans
  • Built-in Functions
  • Closure
  • Comparisons
  • Conditionals
  • Exceptions
  • Falsey Values
  • Functional Javascript (new)
  • Function Expressions
  • Function Expressions as Parameters
  • Functions
  • General Performance
  • Hoisting
  • Logical Assignment
  • Loops
  • Namespaces
  • Numbers
  • Object Prototype
  • Objects
  • Objects Functionality
  • Prototypes
  • Strings
  • Switch Block
  • Ternary Conditionals
  • Truthy Values
  • Variables

Tools

Arrays

  /* An array is a data structure with automatically indexed positions*/
  it('Arrays can be accessed by indices', function () {
    //The brackets indicate to the compiler to make an array and to fill it with
    //the comma-separated values between the brackets
    var arrayOfStrings = [ "StringZero" , "StringOne" , "StringTwo"];
    //We can access any location of the zero-based array
    expect(arrayOfStrings[1]).toBe("StringOne");
  });
  it('You can reference and change specific cells with indices', function () {
    var arrayOfStrings = [ "StringOne" , "StringOne" , "StringTwo"];
    arrayOfStrings[0] = "StringZero"; //You can change the value contained at any index
    expect(arrayOfStrings[0]).toBe("StringZero");
  });

Functions

/*Functions take some input, then execute a series of statements using the input, and outputs a result*/
it('functions help write reusable code', function () {
  expect(addNumbers(1, 2)).toBe(3);
  expect(addNumbers(2, 3)).toBe(5);
  expect(addNumbers(1 + 1, 2 + 1)).toBe(5);//Parameters can also be expressions, which the function will resolve before starting
  var numberOne = 2;
  var numberTwo = 3;
  expect(addNumbers(numberOne, numberTwo)).toBe(5);//Parameters can also be variables
});

// function keyword tells the compiler that you are defining a function
function addNumbers(numberOne, numberTwo) { //The function's name follows the 'function' keyword and should indicate the function's purpose
  //Parameters are passed in a set of parentheses before the first curly brace
  return numberOne + numberTwo;
  //The return keyword works as a terminating statement and exits the function returning the value in front of it
} //The statements that will be executed should be enclosed in curly braces.

Numbers

it('JavaScript uses binary floating point values to handle all of its decimal based operations', function () {
  expect(0.1 + 0.2).toBe(0.30000000000000004);
});
it('You can use the toFixed() method to select the amount of decimal places to display', function () {
  expect((0.1 + 0.2).toFixed(1)).toBe('0.3');
});
it('toFixed() method will round to the last indicated position', function () {
  //0.18 + 0.28 = 0.46
  expect((0.18 + 0.28).toFixed(1)).toBe('0.5');
});
it('parseFloat() turns strings with decimals into numbers', function () {
  expect(parseFloat((0.18 + 0.28).toFixed(1))).toBe(0.5);
});
it('parseInt() looks for the first available integer at the front of a string', function () {
  expect(parseInt("55")).toBe(55);
  expect(parseInt("55 is a great number")).toBe(55);
});
it('if parseInt() does not find an acceptable value at the beginning of a string, it will return a NaN', function () {
  expect(parseInt("A great number, 55")).toBeNaN();
});
it('parseInt() will trim off any decimals that may exist, without rounding', function () {
  expect(parseInt("5.78")).toBe(5);
});
it('parseInt() will accept octal,hexadecimal and decimal values potentially creating undesired results', function () {
  //"021" is read as an octal value(base 8) and converts it to decimal
  expect(parseInt("021")).toBe(17);//This is fixed on ECMAScript5
});
it('you can use a radix value to ensure correct parsing', function () {
  //parseInt will accept any radix value from 2-36 for selecting the Base for the result
  expect(parseInt("021", 10)).toBe(21);
});

Anonymous Closures

//When you create NAMESPACES, the program may still execute its private methods and variables
//It is good practice to use private methods to safely modify private data
//Anonymous Closures allow you to define public and private variables
it('Closures will allow you to make private variables and properties', function () {
  //You can achieve this by surrounding the entire set of properties and values in an immediately
  //invoked function expression
  //The local values and methods will be "closed" into the namespace
  var NAMESPACE = (function () {
    var privateArray = [1, 2, 3];
    var privateVariable = 9;
    //In order to make public properties, you can return an object
    return {
      //Since the function expression is invoked, this returned object will be handled immediately
      // to the NAMESPACE variable and become a namespace
      publicArray: function () {
        return [4, 5, 6];
      },
      publicVariable: 10 + privateVariable
    };
  })();//These parentheses indicate that the function expression should be immediately executed
  //Since privateArray and privateVariable are private, we expect them to be undefined
  expect(NAMESPACE.privateArray).toBeUndefined();
  expect(NAMESPACE.privateVariable).toBeUndefined();
  expect(NAMESPACE.publicArray()).toEqual([4, 5, 6]);
  expect(NAMESPACE.publicVariable).toBe(19);
});

Prototypes

/*Class :  Set of Objects that inherit properties from the same prototype*/

  it('You can create Constructors that allow to set up inheritance while also assigning specific property values', function () {
    //Capitalizing this function's name distinguishes it as a maker of an entire "Class" of objects
    function Person (firstName, lastName ,age){
      //'this' keyword inside a constructor will automatically refer to the new instance of the class that is being made
      this.firstName = firstName;
      this.lastName = lastName;
      this.age = age;
    }

    //'new' keyword produces a new Object of the specified class
    var martinPerson = new Person("Martin", "Chavez", 27);

    expect(martinPerson.firstName).toBe("Martin");
    expect(martinPerson.lastName).toBe("Chavez");
    expect(martinPerson.age).toBe(27);
  });

  it('You can assign a prototype to a constructor', function () {
    function Person (firstName, lastName ,age){
      this.firstName = firstName;
      this.lastName = lastName;
      this.age = age;
    }
    //Setting a constructor prototype property allows the instances to access these properties
    Person.prototype = {
      address: "House 123"
    };
    var martinPerson = new Person("Martin", "Chavez", 27); //There is no need to define the address for each person
    expect(martinPerson.address).toBe("House 123");

  });
  it('You can modify the message functions in a prototype to use the data values in the calling instance', function () {
    function Person (firstName, lastName){
      this.firstName = firstName;
      this.lastName = lastName;
    }

    Person.prototype = {
      //'this' keyword searches for the particular Object(Person) that called the inherited function and retrieves the data from it
      fullName: function() { return(this.firstName + " " + this.lastName); }
    };
    var martinPerson = new Person("Martin", "Chavez");

    expect(martinPerson.fullName()).toBe("Martin Chavez");
  });

  it('You can use prototype chaining to reuse functionality', function () {
    function Person (firstName, lastName){
      this.firstName = firstName;
      this.lastName = lastName;
      this.blackHair = true;
    }

    function Baby(firstName, lastName){
      //You can call the Person constructor within the Baby constructor
      Person.call(this,firstName, lastName);
      // We need to add a reference to this Object constructor, otherwise it will use the Person constructor
      this.constructor = Baby;
    }

    // By setting a parent object as a constructors prototype, objects build with that construct gain access to
    // all the methods on that object, including the methods on its constructor prototype.
    Baby.prototype = new Person();

    // You can also add specific methods to this prototype
    Baby.prototype.cry = function(){
      this.isCrying = true;
    };

    var baby = new Baby("Martin", "Chavez");
    baby.cry();

    // Property from the Baby object
    expect(baby.isCrying).toBeTruthy();
    expect(baby.firstName).toBe("Martin");
    expect(baby.lastName).toBe("Chavez");
    expect(baby.constructor).toBe(Baby);
    // Property from the Person object
    expect(baby.blackHair).toBe(true);
  });

Install (Works on any platform)

npm install --global npm@latest (if you don't have it already)
npm install --global yo bower grunt-cli
cd LearnJavascript
npm install
bower install

Run the Tests

grunt test

Run the tests

Author

Martin Chavez

Continue Learning




鲜花

握手

雷人

路过

鸡蛋
该文章已有0人参与评论

请发表评论

全部评论

专题导读
热门推荐
阅读排行榜

扫描微信二维码

查看手机版网站

随时了解更新最新资讯

139-2527-9053

在线客服(服务时间 9:00~18:00)

在线QQ客服
地址:深圳市南山区西丽大学城创智工业园
电邮:jeky_zhao#qq.com
移动电话:139-2527-9053

Powered by 互联科技 X3.4© 2001-2213 极客世界.|Sitemap