What are the conditions of if statement in js

JavaScript’s if statement uses a conditional expression to determine whether to execute a block of code. Conditional expressions can be: Basic types (numbers, strings, etc.) Objects (not null or undefined) Functions (even if there is no return value) Comparison operators Logical operators

Conditions for if statements in JavaScript

The if statement in JavaScript uses a conditional expression to determine whether to execute a block of code. A conditional expression is a Boolean expression that evaluates to true or false.

The syntax of the if statement is as follows:

<code>if (condition) {
  // 执行 if 语句块
}</code>

Among them, condition is a Boolean expression.

The conditions of the if statement can be of the following types:

• Basic types: Such as numbers, strings, Boolean values, and undefined. These types directly evaluate to true or false in the if statement.
• Objects: Objects are treated as truthy values ​​in JavaScript unless they are null or undefined.
• Functions: Functions are considered truthy values ​​in JavaScript, even if they have no return value.
• Comparison Operators:You can use operators such as ==, ===, >, <, >= and <= together with the operands in the condition use.
• Logical operators: You can use logical operators such as &&, ||, and ! with multiple operands in a condition.

Example:

// 使用基础类型
let num = 10;
if (num > 5) {
  // 代码块执行
}

// 使用对象
let obj = { name: "John Doe" };
if (obj) {
  // 代码块执行
}

// 使用比较运算符
let a = 5, b = 10;
if (a < b) {
  // 代码块执行
}
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