How Does the `= _` Assignment Work in JavaScript?

Understanding the = _ Assignment in JavaScript

In JavaScript, the = _ assignment operator is used to assign a numeric value to a variable. It comprises the following elements:

• =: Assignment operator
• : Unary plus operator
• _: Variable name or expression

Breakdown of the Operator

• =: Assigns the value resulting from the right-hand side operation to the left-hand variable.
• : Attempts to convert the value on its right-hand side to a numeric type (number). If successful, the numeric value is assigned. Otherwise, NaN (Not-a-Number) is assigned.
• _: Represents the variable or expression whose value is converted to a number and assigned to the left-hand variable.

Example:

<code class="javascript">hexbin.radius = function(_) {
   if (!arguments.length)
       return r;
   r = +_;
   dx = r * 2 * Math.sin(Math.PI / 3);
   dy = r * 1.5;
   return hexbin;
};</code>

In this example:

• _ is a function argument that represents the radius value.
• _ converts the _ argument to a number and assigns it to the r variable.
• The subsequent calculations are based on the numeric value of r.

Additional Details:

• • is the preferred method for converting values to numbers due to its speed and efficiency.

• The following values can be converted to numbers using :

  • String representations of integers and floats, e.g., "1"
  • Non-string values true, false, and null
  • Decimal and hexadecimal integers
• If the conversion is unsuccessful, NaN is assigned.

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