Explain the use of the << operator for left shift in JavaScript.

In JavaScript, the `<<` operator is the left shift operator. It performs a bitwise left shift operation on the binary representation of a number, shifting the bits to the left by a specified number of positions.

The syntax is as follows:

result = operand << shiftCount;

- `operand`: The number to be shifted.

- `shiftCount`: The number of positions to shift the bits to the left.

Here's a simple example:

let num = 5;  // Binary: 0101

let result = num << 2;

console.log(result);  // Outputs: 20 (Binary: 10100)

In this example:

- The binary representation of `num` is `0101`.

- The `<< 2` operation shifts the bits two positions to the left, adding zeros to the right.

- The result is `10100`, which is `20` in decimal.

Left shifting a number by `n` positions is equivalent to multiplying the number by `2^n`. In the example above, `5 << 2` is equivalent to `5 * 2^2`, which equals `20`.

It's important to note that the left shift operation is a quick way to perform a multiplication by powers of 2. However, keep in mind that left shift may lead to unexpected results if the shifted value exceeds the representation limits of JavaScript's numeric types (32-bit signed integers). Additionally, left shifting negative numbers may result in different behavior due to the two's complement representation of negative integers in binary.