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What is an Instance in JS?

This is the object which is created from a constructor function.

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What is dunder proto in JS

dunder proto === __proto__

Every object in JS has this property.

It points back to the prototype object of the constructor function that created that object.

Only Object.prototype.__proto__ === null

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Prototype Property in JS

When a new function is created a new property is added to it. That property is named prototype. It's an object and initially has two properties:

• constructor: which points to the function itself;
• __proto__

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Autoboxing in JS

// calling String function like this
// will try to create a primitive value of type string from the argument which 
// is passed to the String function
String("chair") // the result is "chair"

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Constructor Functions in JS

If you have several objects that share the same implementation, you can use a constructor function to create them.

Any function can be a constructor function as long as it is invoked using the new keyword

function createSillyExample() {}

const objectCreatedFromSillyExample = new createSillyExample();

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Typescript

Installation

Global installation

npm i -g typescript

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Functional Programming

Pure Functions

• a fn which uses only its arguments and/or local variables to compute its result
• a fn which does not cause side effects

Todo: Function Composition

Higher Order Function

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Tips for building APIs

Time and Dates

• The 5 laws of API dates and times

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Regular Expressions

Tools

Online regex tester and debugger

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Testing with Jest

npm i --save-dev jest

package.json

{