JavaScript Assignment Operators
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JavaScript provides a range of assignment operators to manipulate variables and values. Assignment operator in js is an element that helps in the process of assigning values to variables. It is a symbol or a combination of symbols used to assign a value on the right side to a variable on the left side. The equal sign(=) is the mostly used and common assignment operator. Let us explore the syntax, parameters, and examples of different assignment operators in JavaScript.
Syntax for Assignment Operator in JS
The assignment operator in JavaScript is represented by the equal sign (=). The syntax follows a pattern where a variable on the left is assigned a value on the right. The syntax for assignment operator in js is:
Parameters for Assignment Operator in JS
Assignment operators in JavaScript take two operands:
- variable:
This is the identifier representing the storage location (memory) where the value will be stored. - value:
This is the expression or literal value that is assigned to the variable.
The =(equal sign) is the assignment operator and signifies that the value on the right side will be assigned to the variable on the left side.
Return Value for Assignment Operator in JS
The assignment operation in js has no specific return value and is used for the purpose of assigning a value to a variable.
Example for Assignment Operator in JS
Let us consider the following example to illustrate the working of the assignment operator in javascript.
Explanation
In this line, a variable is the decalared to holds the value Learning. It serves as a reference to a location in memory where data is stored. We can use the let, const, or var keyword, followed by a variable name for declaring a variable. Explore the difference between the three different keywords.
The equal sign is the assignment operator. It signifies that the value on the right side of the expression will be assigned to the variable on the left. Now, see the following line,
The assignment operator in js is used again to update the value of the scaler variable.
Output
Initially, the scaler variable is assigned the value "Learning," which is printed first and then it is updated to "Courses for learning" using the assignment operator.
JavaScript Assignment Operators
JS Assignment Operators
| Operator Symbol | Name | Example | Expanded Form |
|---|---|---|---|
| = | Assignment | a = 1; | a = 1; |
| += | Addition assignment | x += 3; | x = x + 3; |
| -= | Subtraction assignment | x -= 3; | x = x - 3; |
| *= | Multiplication assignment | x *= 3; | x = x * 3; |
| **= | Exponentiation assignment | x **= 3; | x = x ** 3; |
Shift Assignment Operators
| Operator Symbol | Name | Example | Expanded Form |
|---|---|---|---|
| <<= | Left shift assignment | x <<= 3; | x = x << 3; |
| >>= | Right shift assignment | x >>= 3; | x = x >> 3; |
| >>>= | Unsigned right shift assignment | x >>>= 3; | x = x >>> 3; |
Bitwise Assignment Operators
| Operator Symbol | Name | Example | Expanded Form |
|---|---|---|---|
| &= | Bitwise AND assignment | x &= 3; | x = x & 3; |
| |= | Bitwise OR assignment | x |= 3; | x = x | 3; |
| ^= | Bitwise XOR assignment | x ^= 3; | x = x ^ 3; |
Logical Assignment Operators
| Operator Symbol | Name | Example | Expanded Form |
|---|---|---|---|
| &&= | Logical AND assignment | x &&= true; | x = x && true; |
| ||= | Logical OR assignment | x ||= true; | x = x || true; |
| ??= | Nullish coalescing assignment | x ??= 3; | x = x !== null && x !== undefined ? x : 3; |
Examples
The = Operator
The assignment operator in js is used to assign a value to a variable.
The += Operator
The addition assignment operator adds the value on the right side to the existing value of the variable on the left side.
The -= Operator
The subtraction assignment operator subtracts the value on the right side from the existing value of the variable on the left side.
The *= Operator
The multiplication assignment operator multiplies the existing value of the variable on the left side by the value on the right side.
The **= Operator
The exponentiation assignment operator raises the existing value of the variable on the left side to the power of the value on the right side.
Example:
Explanation:
In this example, b initially has the value 2. The **= operator raises b to the power of 3. After the operation, b becomes 8.
The /= Operator
The division assignment operator ivides the existing value of the variable on the left side by the value on the right side.
The %= Operator
The remainder assignment operator calculates the remainder when dividing the existing value of the variable on the left side by the value on the right side.
The <<= Operator
The left shift assignment operator shifts the bits of the existing value of the variable on the left side to the left by the number of positions specified on the right side.
Example:
Explanation:
Here, a initially has the binary value 1000 (8 in decimal). The <<= operator shifts the bits to the left by 2 positions, resulting in 001000 in binary, which is 32 in decimal.
The >>= Operator
The right shift assignment operator shifts the bits of the existing value of the variable on the left side to the right by the number of positions specified on the right side.
Example:
Explanation:
In this example, b initially has the binary value 10000 (16 in decimal). The >>= operator shifts the bits to the right by 2 positions, resulting in 00100 in binary, which is 4 in decimal.
The >>>= Operator
The unsigned right shift assignment operator shifts the bits of the existing value of the variable on the left side to the right by the number of positions specified on the right side, filling the leftmost positions with zeros.
Example:
Explanation of Example:
Here, c initially has the binary representation with sign bits 0100 (4 in decimal). The >>>= operator shifts the bits to the right by 2 positions, filling the leftmost positions with zeros. After the operation, c becomes 1 in decimal.
The &= Operator
The bitwise AND assignment operator performs a bitwise AND operation between the existing value of the variable on the left side and the value on the right side, updating the variable with the result.
Example:
Explanation:
In this example, x initially has the binary value 101 (5 in decimal). The &= operator performs a bitwise AND operation with 3 (binary 011). The result of the operation is 1 in decimal or 001 in binary. After the operation, x becomes 1.
The |= Operator
The bitwise OR assignment operator in javascript performs a bitwise OR operation between the existing value of the variable on the left side and the value on the right side, updating the variable with the result.
Example:
Explanation:
Here, x initially has the binary value 1000 (8 in decimal). The |= operator performs a bitwise OR operation with 3 (binary 100). The result is 1100 in binary, which is 12 in decimal. After the operation, y becomes 12.
The ^= Operator
The bitwise XOR assignment operator in js performs a bitwise XOR operation between the existing value of the variable on the left side and the value on the right side, updating the variable with the result.
Example:
Explanation: In this example, z initially has the binary value 101 (5 in decimal). The ^= operator performs a bitwise XOR operation with 3 (binary 011). The result is 110 in binary, which is 6 in decimal. After the operation, z becomes 6.
The &&= Operator
The logical AND assignment operator checks if the current value of the variable on the left side is truthy. If it is, it updates the variable with the right operand. Explore about truthy and fasly in Javascript.
The ||= Operator
The logical OR assignment operator checks if the current value of the variable on the left side is false. If it is, it updates the variable with the right operand.
The ??= Operator
The ??= operator is the nullish coalescing assignment operator. It checks if the current value of the variable on the left side is null or undefined. If it is, it updates the variable with the right operand.
Example:
Explanation:
Here, c initially has the value null. The ??= operator checks if c is null or undefined. Since it is, c is updated with the right operand (2). After the operation, c becomes 2.
Conclusion
- Assignment operators in js are essential for assigning values to variables. Assigning a value to a variable can be done using the assignment operator (=), while others like +=, -= offer shorthand ways of performing addition or subtraction with assignment.
- Shift assignment operators (<<=, >>=, >>>=) are useful for bitwise operations, manipulating binary representations of integers.
- Bitwise assignment operators (&=, |=, ^=) perform bitwise AND, OR, XOR operations with assignment, useful for bit manipulation.
- Logical assignment operators (&&=, ||=, ??=) combine logical operations with assignment, offering a easier ways to update variable values based on conditions.