Interesting JavaScript hacks that make things easier

As a programmer i always like to look for different ways to doing things to see if i can improve my timing or how my code look. This are some examples of code that i found interesting in JavaScript

1. Shuffle elements from array

Every day I’m shufflin’

var my_list = [1, 2, 3, 4, 5, 6, 7, 8, 9];
console.log(my_list.sort(function() {
    return Math.random() - 0.5
})); 
// [4, 8, 2, 9, 1, 3, 6, 5, 7]

2.Use length to resize/empty an array

We basically overwrite the length of the array.

If we want to resize the array:

var entries = [1, 2, 3, 4, 5, 6, 7];  
console.log(entries.length); 
// 7  
entries.length = 4;  
console.log(entries.length); 
// 4  
console.log(entries); 
// [1, 2, 3, 4]

If we want to empty the array:

var entries = [1, 2, 3, 4, 5, 6, 7]; 
console.log(entries.length); 
// 7  
entries.length = 0;   
console.log(entries.length); 
// 0 
console.log(entries); 
// []

3. Convert number to string

We just have to use the concatenation operator with an empty set of quotation marks.

var converted_number = 5 + "";
console.log(converted_number);
// 5
console.log(typeof converted_number); 
// string

4. Convert string to number

All we need is the + operator.

Be careful with this one since it only works with ‘string numbers’.

the_string = "123";
console.log(+the_string);
// 123
the_string = "hello";
console.log(+the_string);
// NaN

5. Replace All

We know that the string.replace() function replaces only the first occurrence.
You can replace all the occurrences by adding /g at the end of the regex.

var example = "potato potato";
console.log(example.replace(/pot/, "tom")); 
// "tomato potato"
console.log(example.replace(/pot/g, "tom")); 
// "tomato tomato"

6. Flatten multidimensional array

Simply by using the Spread operator.

var entries = [1, [2, 5], [6, 7], 9];
var flat_entries = [].concat(...entries); 
// [1, 2, 5, 6, 7, 9]

7. Short Circuit Conditionals

Let’s take this example:

if (available) {
    addToCart();
}

And shorten it by simply using the variable together with the function:

available && addToCart()

8. Dynamic Property Names

I always thought that I first had to declare an object before being able to assign a dynamic property.

const dynamic = 'flavour';
var item = {
    name: 'Coke',
    [dynamic]: 'Cherry'
}
console.log(item); 
// { name: "Coke", flavour: "Cherry" }

9. Extract Unique Values

We can create a new array only with the unique values by using the Set object and the Spread operator.

var entries = [1, 2, 2, 3, 4, 5, 6, 6, 7, 7, 8, 4, 2, 1]
var unique_entries = [...new Set(entries)];
console.log(unique_entries);
// [1, 2, 3, 4, 5, 6, 7, 8]