How many parameters can be used to define a function in js

The number of parameters of JavaScript function depends on the design of the specific function, which may be: 1) no parameters; 2) one parameter; 3) multiple parameters; 4) variable number of parameters (rest parameters); 5) Default value parameters.

Number of parameters in JavaScript function definition

JavaScript functions can use the following number of parameters:

0 parameters

• The function does not accept any parameters, for example:

<code class="javascript">function greet() {
  console.log("Hello!");
}</code>

1 parameters

• The function accepts one parameter, for example:

<code class="javascript">function greet(name) {
  console.log("Hello, " + name + "!");
}</code>

Multiple parameters

• The function can accept multiple parameters, for example ：

<code class="javascript">function calculateArea(length, width) {
  return length * width;
}</code>

Variable number of parameters (rest parameters)

• Use ... operators to define rest parameters, Indicates that the function can accept any number of parameters, for example:

<code class="javascript">function sum(...numbers) {
  let total = 0;
  for (const num of numbers) {
    total += num;
  }
  return total;
}</code>

Default value parameters

• Use the = operator definition Default value parameter, indicating that the default value is used when the corresponding parameter is not provided, for example:

<code class="javascript">function greet(name = "John") {
  console.log("Hello, " + name + "!");
}</code>

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