JavaScript Operations

1. Introduction

2. What is an Operator?

          In the expression 7 + 3 = 10, 7 and 3 are operands and the '+' sign is the operator. 

          There are different types of operators that are being supported by JavaScript. These are the following operators: 

• Arithmetic Operators 
• Comparison Operators 
• Logical Operators 
• Assignment Operators 
• Ternary Operators

2.1. Arithmetic Operators

          Suppose you have variables a = 20 and b = 30. You can apply the following operations

• Addition (+): Adds two operands Ex. a + b will result to 50. 
• Subtraction (-): Subtracts the second operand from the first Ex. a – b will result to -10. 
• Multiplication (*): Multiply both operands Ex. a * b will result to 600. 
• Division (/): Divide the numerator by the denominator Ex. b / a will result to 1.5. 
• Modulus (%): Outputs the remainder of an integer division Ex. a % b will result to 20. 
• Increment (++): Adds one to its operand. Ex. a++ will result to 21. 
• Decrement (--): Subtracts the second operand from the first Ex. a-- will result to 19.

          For incrementing and decrementing, if a prefix operator (++x or --x) is used, it will return the value of the operand after adding one. Meanwhile, the postfix operator (x++ or x--) will return the value of the operand before adding one. For example, if x = 5, then ++x sets x to 6 and returns 6, while x++ returns 5 and, only then, sets x to 6.

Sample code:

Output:

2.2. Comparison Operators

          To compare two values, you can use the JavaScript comparison operators. Supposed a = 20 and b = 30, let us try to compare the two values: 

• Equal (==): It checks whether the two values are equal or not. If the two values are equal, then the condition is true. Ex. a == b is false. 
• Not Equal (!=): It checks whether the two values are equal or not. If the two values are not equal, then the condition is true. Ex. a != b is true. 
• Greater than (>): It checks whether the value on the left side is greater than the right. If yes, then the condition is true. Ex. a > b is false.
• Less than (<): It checks whether the value on the left side is less than the right. If yes, then the condition is true. Ex. a < b is true. 
• Greater than or Equal to (>=): It checks whether the value on the left side is greater than or equal to the right. If yes, then the condition is true. 

•  Less than or Equal to (<=): It checks whether the value on the left side is less than or equal to the right. If yes, then the condition is true. 

•  Strictly Equal (===): It checks whether the two values are equal and of the same type. If yes, then the condition is true. Ex. a === "20" is false. 
• Strictly Not Equal (!==): It checks whether the two values are not equal and not of the same type. If yes, then the condition is true. Ex. a !== "20" is true.

          Take note that in strictly equal and strictly not equal operations, it does not only check whether the two values are equal but also if they are of the same type. In the example given, variable a is an integer type of data while "20" is a string. So, if we compare a === "20", the result is false. It is because even if both of them are of the same value (20), these two are not of the same type. 

Sample Code:

Output:

2.3. Logical Operators

          Logical operators are usually used with conditional operations and will return a Boolean value. However, if these operators are used with non-Boolean values, it may return a non-Boolean value. 

• Logical AND (&&): For Boolean operands, it will return true if both operands are true; otherwise, it will return false. For non-Boolean operands, it will return the operand on the left if it can be converted to false; otherwise, it will return the operand on the right. 

• Logical OR (||): For Boolean operands, it will return false if both operands are false; otherwise, it will return true. For non-Boolean operands, it will return the operand on the left if it can be converted to true; otherwise, it will return the operand on the right.

• Logical NOT(!): It returns true if the operand is evaluated to false; otherwise, returns false. 

2.4. Assignment Operators

          There is a difference between using one equal sign (=), two equal signs (==) and three equal signs (===). The two and three equal signs are used to compare values and data types of two operands. One equal sign (=) is not used to compare values but rather assigns the value of the right operand to the left. For example, you can assign the value of y to x by simply writing x = y. 

          There are compound assignment operators that can be written in shorthand form. The table below summarized the shorthand assignment operators.

Sample Code:

Output:

3. Summary and References

In summary,

• JavaScript includes operators that perform some operation on single or multiple operands (data value) and produce a result. 
• JavaScript includes various categories of operators: Arithmetic operators, Comparison operators, Logical operators, Assignment operators

References: