How to write if judgment in nodejs

In Node.js, writing if judgments is not much different from writing if judgments in other programming languages. In Node.js, the syntax of if statements is the same as in JavaScript.

The syntax of the if statement is as follows:

if (expression) {
  // 当表达式的值为true时执行的代码
} else {
  // 当表达式的值为false时执行的代码
}

Among them, expression is the expression that needs to be judged, and can be any expression whose calculation result is a Boolean value.

The following are a few examples of how to write if judgments in Node.js:

1. Judge whether two variables are equal:

let a = 5;
let b = 7;
if (a === b) {
  console.log('a和b相等');
} else {
  console.log('a和b不相等');
}

Output results For: a and b are not equal

2. Determine whether a value is greater than 10:

let num = 5;
if (num > 10) {
  console.log('num大于10');
} else {
  console.log('num小于等于10');
}

The output result is: num is less than or equal to 10

3. Determine whether a string is empty:

let str = '';
if (str) {
  console.log('str不为空');
} else {
  console.log('str为空');
}

The output result is: str is empty

In addition to the basic if statement, Node.js also provides other types of judgment statements, For example, switch statement and ternary operator. These can be used to implement more complex conditional judgment logic.

Summary: In Node.js, the if statement has the same syntax as in JavaScript and can be used to handle various conditional judgment logic. Developers can choose different judgment statements to implement corresponding functions according to specific needs.

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