By Klaus Camarena

Translation: Crazy geek

Original text: dev. To/razgandeanu…

Reproduced without permission

Here are 9 powerful JavaScript hacks.

1. Replace all

We know that string.replace() only replaces the first occurrence.

You can replace all occurrences by adding /g to the end of the regular expression.

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

2. Extract unique values

By using the Set object and the expansion operator, we can create a new array with unique values.

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]
Copy the code

3. Convert numbers to strings

We just need to use the concatenation operator with empty quotes.

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

4. Convert strings to numbers

All we need is the + operator.

Note that it only applies to “string numbers”.

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

the_string = "hello";
console.log(+the_string);
// NaN
Copy the code

5. Randomly arrange the elements in the array

I do it every day

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]
Copy the code

6. Flatten multidimensional arrays

Just use the expansion operator.

var entries = [1[2.5], [6.7].9];
varflat_entries = [].concat(... entries);// [1, 2, 5, 6, 7, 9]
Copy the code

7. Shorten conditional statements

Let’s look at this example:

if (available) {
    addToCart();
}
Copy the code

Shorten it by simply using variables and functions:

available && addToCart()
Copy the code

8. Dynamic property names

I always thought you had to declare an object before you could assign dynamic properties.

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

9. Use length to adjust/empty the 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]
Copy the code

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); 
/ / []
Copy the code

Welcome to pay attention to the front public number: front pioneer, free webpack from the entry to the full series of advanced tutorials.