Tuples
A tuple is a collection which is ordered and unchangeable or immutable.
Month: June 2020
JavaScript `this` keyword
In order to find more details about this usage, follow link below.
https://www.w3schools.com/Js/js_this.asp
I just took the following part from that page.
JavaScript ES6 Classes and Arrow Functions
I try to understand difference between function expression, shorthand method definition, arrow function and bind().
Notice that I defined sayGoodBye() function in constructor, it means that whenever i create a new instance from this Person class, sayGoodBye() function will be defined for every instance.
sayHello() function is defined as a class property. But, as you can see in the following screenshot, class properties are also defined in constructor so class properties are just a sugar syntax.
getFullName() function is defined as shorthand method definition. But, Babel didn't move function definition in class constructor. So, if we use shorthand method definition in class, it will be a prototype function .
It mean they are only defined once, instead of once per instance.
Notice that in below screenshot, getFullName() function is in prototype of Person class, but sayHello() and sayGoodBye() are not.
JavaScript Three Ways of Handling Asynchronous Operations
There is one more post about Promise and Async/Await usage in the following link.
There are 3 ways to handle asynchronous function calls.
Using Callbacks
Node.js Mocha and Chai
Mocha is a test framework to run tests.
https://mochajs.org/#assertions
Chai is an assertion library and you can find full documentation in the following link.
https://www.chaijs.com/api/bdd/
There are three type of assertion libraries in Chai.
- Expect
- Should
- Assert
expect and should use the same chainable language to construct assertions.
Assume that expect library is used like below
expect(firstName).to.be.a('string');
expect(firstName).to.equal('kenan');
expect(firstName).to.have.lengthOf(5);
expect(beverages).to.have.property('tea').with.lengthOf(3);Above code could be written with should library like below.
firstName.should.be.a('string');
firstName.should.equal('kenan');
firstName.should.have.lengthOf(5);
beverages.should.have.property('tea').with.lengthOf(3);You can find more detailed usage with Express, Mocha and Chai in the following repository
https://github.com/nodejs-projects-kenanhancer/express-demo.git
Continue readingNode.js Object Field Filter Algorithm
Find Interaction Algorithm
FindIntersection(strArr) read the array of strings stored in strArr which will contain 2 elements: the first element will represent a list of comma-separated numbers sorted in ascending order, the second element will represent a second list of comma-separated numbers (also sorted). Your goal is to return a comma-separated string containing the numbers that occur in elements of strArr in sorted order. If there is no intersection, return the string false.
Demo 1
Continue readingTypeScript Utility Types
You can see examples in the pictures and more demo codes in the rest of post.
Type Inference
ConstructorParameters<T>
Syntax
Examples
InstanceType<T>
Syntax
Examples
ReturnType<T>
Syntax
Examples
Parameters<T>
Syntax
Examples
NonNullable<T>
Syntax
Examples
Extract<T, U>
Syntax
Examples
Exclude<T, U>
Syntax
Examples
Demo 1
Continue readingTypeScript Usage of Namespace, Interface, Class, Abstract Class, Type Alias
Demo 1
Demo 2
TypeScript Enum to Builder Pattern
I just want to create some demo for enum to create a builder . I improved this concept step by step in demos. Notice that all the codes are doing same job but in a different way.