10 JavaScript Topics Every Developer need to know

Null vs Undefined

Undefined: Undefined means that, a variable is declared but not assigned any value.
Null: It’s an assignment value. It can be assigned to a variable as a representation of no value.
Null and undefined are equal in value but different in type.

Truthy and Falsy values

All values are truthy unless they are defined as falsy.
Truthy values: true, {}, [], 112, '0', "false", new Date(), -92, 12n, 3.1416, -3.1416, Infinity, -Infinity
Falsy values:
false, null, undefined, NaN, 0, -0, 0n, '', ""(Empty string)

Double Equal(==) vs Triple Equal(===)

Double Equal only check the values but Triple Equal check the values and data type.

Implicit Conversion vs Explicit Conversion

When JS automatically converts a data type of a variable, then it’s called Implicit conversion. Also, we can convert data types manually. It’s called Explicit Conversion.

if need to convert manually: