1. String to a number
Now you can easily convert a string to a number by just only using
+ the sign. Unlike the old method, using the
+ operator is much cleaner and easier.
my_string = "123"; console.log(+my_string); // 123 my_string = "amazing"; console.log(+my_string); // NaN
Please note that it only works with string numbers as you can see in the example above.
2. A number to a string
Have a look at this:
let converted_number = 5 + ""; console.log(converted_number); // 5 console.log(typeof converted_number); // string
3. Get unique values
We can extract unique values from an array i.e removing duplicate values in an array by simply using the Set object and Spread operator.
let array_values = [1, 3, 3, 4, 5, 6, 6, 6,8, 4, 1] let unique_values = [...new Set(array_values )]; console.log(unique_values ); // [1,3, 4, 5, 6, 8]
4. Replace all
In our example, we'll use global regex /g to replace all occurrences of a string.
let replace_string = "Visit stunnitysoft. stunnitysoft is a software company"; console.log(replace_string.replace(/stunnity/, "Micro")); // "Visit Microsoft. stunnitysoft is a software company" console.log(replace_string.replace(/stunnity/g, "Micro")); // "Visit Microsoft. Microsoft is a software company"
5. Optional Chaining
The optional chaining operator (?.) permits reading the value of a property located deep within a chain of connected objects without having to expressly validate that each reference in the chain is valid.
- Taken from MDN DOCS
Let's consider the expression
This expression evaluates to
a.b if a is
not null and
not undefined, otherwise, it evaluates to
You can also chain this multiple times like
If a is
null, then this expression evaluates to undefined
b is undefined or null, then this expression evaluates to undefined
Else this evaluates to
obj.val?.prop obj.val?.[expr] obj.arr?.[index] obj.func?.(args)
6. Nullish Coalescing Operator
The nullish coalescing operator (??) is a logical operator that returns its right-hand side operand when its left-hand side operand is null or undefined, and otherwise returns its left-hand side operand.
Taken from MDN DOCS
Consider the expression
a ?? b. This evaluates to
b if a is
undefined, otherwise, it evaluates to
7. Logical AND (&&) and Logical OR (||) Operators
Logical AND (&&) Operator
Let's say we have the following expression where b and c are expressions.
b && c
This will be evaluated to the value of c only if
bis truthy, otherwise, it will be evaluated to the value of
- If b is falsy, then the expression c is not even going to be evaluated.
- This is called short-circuit evaluation.
- This is very useful while using React.
Logical OR (||) Operator
Let's say we have the following expression where b and c are expressions. b || c
This will be evaluated to the value of b if b is truthy, otherwise, it will be evaluated to the value of c.
- Short-circuit evaluation happens here too.
- If b is truthy, then the expression c is not even going to be evaluated.
- This is also used often in React.
8. Using length to resize and emptying an array
let array_values= [1, 2, 3, 4, 5, 6, 7, 8]; console.log(array_values.length); // 8 array_values.length = 5; console.log(array_values.length); // 5 console.log(array_values); // [1, 2, 3, 4,5]
Emptying an array
let array_values= [1, 2, 3, 4, 5, 6, 7,8]; console.log(array_values.length); // 8 array_values.length = 0; console.log(array_values.length); // 0 console.log(array_values); // 
Note: Setting the length to 0 is not advisable as it can lead to a memory leak. In order to clean objects in an array from memory, they need to be explicitly removed.
This was too long but thank you for holding on until the last line 😊, I hope this article was helpful, and if so please share it to other people who can find it useful. Feel free to give a suggestion or shoot me a message on C4TBT