SOLID / DRY principles

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In software development, Object-Oriented Design plays a crucial role when it comes to writing flexible, scalable, maintainable, and reusable code. There are so many benefits of using OOD but every developer should also have the knowledge of the SOLID principle for good object-oriented design in programming. The SOLID principles are designed to help developers design robust, maintainable applications. The five SOLID principles are: Single-responsibility principle - Function and classes should have one job. Open–closed principle - Classes and functions should be open for  extension but not for modification. Liskov substitution principle - Child class can replace parent class Interface segregation principle - This principle is the first principle that applies to Interfaces instead of classes in SOLID and it is similar to the single responsibility principle. It states that “do not force any client to implement an interface which is irrelevant to them“. Here your main goal is ...
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Difference between == and === operators

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 JavaScript provides both strict(===, !==) and type-converting(==, !=) equality comparison. The strict operators take type of variable in consideration, while non-strict operators make type correction/conversion based upon values of variables. The strict operators follow the below conditions for different types,

  1. Two strings are strictly equal when they have the same sequence of characters, same length, and same characters in corresponding positions.
  2. Two numbers are strictly equal when they are numerically equal. i.e, Having the same number value. There are two special cases in this,
    1. NaN is not equal to anything, including NaN.
    2. Positive and negative zeros are equal to one another.
  3. Two Boolean operands are strictly equal if both are true or both are false.
  4. Two objects are strictly equal if they refer to the same Object.
  5. Null and Undefined types are not equal with ===, but equal with ==. i.e, null===undefined --> false but null==undefined --> true

Some of the example which covers the above cases,

0 == false   // true
0 === false  // false
1 == "1"     // true
1 === "1"    // false
null == undefined // true
null === undefined // false
'0' == false // true
'0' === false // false
[]==[] or []===[] //false, refer different objects in memory
{}=={} or {}==={} //false, refer different objects in memory

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