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JavaScript Operators

What is an operator?

Simple answer can be given using expression 4+5 is equal to 9, Here 4 and 5 are called operands and + is called operator JavaScript language supports following type of operators.

Arithmetic Operators

Comparison Operators

Logical (or Relational) operators

Assignment Operators

Conditional (or ternary) Operators

Lets have a look on all operators one by one.

Arithmetic Operators

There are following arithmetic operators supported by JavaScript language

Assume variable A holds 10 and variable B holds 20 then

 Operator Description Example + Adds 2 operands A+B will give 30 – Subtract second opened from the first A-B will give -10 * Multiply both operands A*B will give 200 / Divide numerator by denumerator B/A will give 2 % Modulus operator and reminder of after an integer division B%A will give 0 ++ Increment operator , increases integer value by one A++ will give 11 — Decrement operator, decreases integer value by one A—will give 9

Note

Addition operator (+) works for number as well as strings

Ex: “a” +10 will give “a10”

The comparison operators

There are following comparison operators supported by java script language

Assume variable A holds 10 and variable B holds 20 then

 Operator Description Example == Checks if the value of 2 operands are equal or not , if yes then condition become true (A==B) is not true != Checks if the value of 2 operands are equal or not ,if values are not equal then condition becomes true (A!=B) is true > Checks if the value of left operand is grater than the value of right operand, if yes then condition becomes true (A>B) is not true < Checks if the value of left operand is grater than the value of right operand, if yes then condition becomes true (A= Checks if the value of left operand is grater than or equal to the value of right operand if yes then condition becomes true (A>=B) is not true <= Checks if the value of left operand is less than or equal to the value of right operand if yes then condition becomes true (A<=B) is true

Logical Operators

There are following logical operators supported by java script language

Assume variable A holds 10 and variable B holds 20 then

 operator description Example && Called logical AND operator, if both the operands are non zero then condition becomes true (A&&B) is true || Called logical OR operator, if any of the 2 operands are non zero then condition becomes true (A||B) is true ! Called logical NOT Operator. Use to reverses the logical state of its operand .if a condition is true logical NOT operator will make false !(A&&B) is false

Bitwise Operators

There are following logical operators supported by java script language

Assume variable A holds 10 and variable B holds 20 then

 Operator description Example & Called bitwise operator. It performs a Boolean AND operation on each bit of its integer arguments (A&B) is 2 | Called bitwise operator. It performs a Boolean OR operation on each bit of its integer arguments (A|B) is 3 ^ Called bitwise XOR operator. It performs a Boolean exclusive OR operation on each bit of its integer arguments. Exclusive OR means that either operand one is true or operand 2 is true, but not both (A^B) is 1 ~ Called bitwise NOT operator. It is a is a unary operator and operates by reversing all bits in the operand (~B) is 4 << Called bitwise shift left operator. It moves all bits in its 1st operand to the left by the number of places specified iin the second operand. New bits are filled with 0 shifitng a value left by one position is equivalent to multiplying by 2, shifting 2 positions is equivalent to multiply by 4 etc.. (A<<1)is 4 >> Called bitwise shoft right with sign operator. It moves all bits in its 1st operand to the right by the no.of places specified in the 2nd operand. The bits filled in on the left depend on the sign bit of the original operand, in order preserve the sign of the result. If the 1st operand is positive, the result has ones placed in the high bits. Shifting a value right one place is equalling to dividing by 2, shifting right 2 places is equalivalent to integer division by 4, and so on. (A>>1) is 1 >>> Called Bitwise shift right with zero operator. This operator is just like the >> operator, except that the bits shifted in on the left are always zero (A>>>1) is 1

Assignment  Operators

There are following arithmetic operators supported by JavaScript language

Assume variable A holds 10 and variable B holds 20 then

 Operator Description Example = Simple assignment operator, Assign values from right side operands to left side operand C=A+B will assign value of A+B into C += Add AND assignment operator, it add right operand to the left operand and assign the result to left operand C+=A is equivalent to C = C+A -= Subtract AND assignment operator, it subtracts right operand from the left operand and assign the result to left operand C-=A is equivalent to C=c-A *= Multiply AND assignment operator, It multiplies right operand with the left operand and assign the result to left operand C*=A is equivalent to C=C*A /= Divide AND assignment operator, IT divides left operand with the right operand and assign the result to left operand C/=A is equivalent to C=C/A %= Modulus AND assignment operator, it takes modulus using two operands and assign the result to left operand C%=A is equivalent to C=C%A

Note

Same logic applies to Bitwise operator so they will become like <<=,>>=,>>=&=!= and ^=

Miscellaneous Operator

The Conditional Operator (? 🙂

There is an operator called conditional operator. This first evaluates an expression for a true or false value and then execute one of the two given statements depending upon the result of the evaluation. The conditional operator has this syntax:

 Operator Description Example ?= Conditional Expression If condition is true? Then value X: Otherwise value Y

The typeof Operator

The typeof is a unary operator that is placed before its single operand, which can be of any type. its value is a string indicating the data type of the operand.

The typeof operator evaluates to “number” , “string”, or “boolean” if its operand is a number, string, or boolean value and returns true or false based on the evaluation

Here is the list of return values for the typeof Operator:

 Type string returned by typeof Number “number” String “string” Boolean “boolean” object “object” Function “function” Undefined “undefined” Null “object”