Posted in javascript
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2:37 am, March 28, 2022
 

Javascript Objects Notes

As javascript objects are used so often in javascript i thought i would write an overview and some notes on how they work, well how they work for me anyway. I guess how they work for me should be similar to how they just work, so should be good. 

What is a Javascript Object?

  1. A javscript object is a collection of named values.
  2. Objects is an unordered collection of key value pairs.
  3. Javascript Objects are like an array, but not actually an array.  

An example of a Javascript Object

Javascript

const my_object = {
    "my_object_1": "value1",
    "my_object_2": "value2",
    "my_object_3": "value3"
}

Accessing Properties of an Object

Lets take the my_object and access value2 from it. 

You can do this with : objectName.property

or like this

objectName["property"]

Javascript

console.log(my_object.my_object_2);

Convert an Object to An Array

You can convert your javascript object into an array with Object.values(objectName);

Javascript

/* an array of the object called my_object_array */
const my_object_array = Object.values(my_object);
console.log(my_object_array);

Loop throught the new array

Usually i forget how to do this, so i thought i would add it here to see if it jogs my memory. 

The array is now called my_object_array

This seems to work:

Javascript

/* foreach on the array function */
let out = "";
my_object_array.forEach(do_stuff_function);
function do_stuff_function(value, index, array) {
  out += "value: " + value + ", index: " + index + "array: " + array;
}
console.log(out);

Object Methods

You can add things like functions inside objects, which makes them even more useful than arrays. 

add code and example... 

Constructor

A blue print for creating objects. 

 

Javascript

const my_object = {
    "my_object_1": "value1",
    "my_object_2": "value2",
    "my_object_3": "value3"
}
console.table(my_object);

// console.log the value of my_object.my_object_2
console.log(my_object.my_object_2);

// console.log the value of objectName["property"]
console.log( my_object["my_object_2"] );

// an array of the object called my_object_array
const my_object_array = Object.values(my_object);
console.log(my_object_array);

// foreach on the array function
let out = "";
my_object_array.forEach(do_stuff_function);
function do_stuff_function(value, index, array) {
  out += "value: " + value + ", index: " + index + "array: " + array;
}
console.log(out);

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