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Вивчайте What Are Data Types? | Understanding JavaScript Data Types
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JavaScript Data Types Foundations

bookWhat Are Data Types?

Before you can write effective JavaScript, you need to understand the concept of data types. In programming, a data type defines the kind of value a variable can hold and the operations that can be performed on that value. Data types help the programming language know how to interpret and handle the data you use in your code. In JavaScript, data types are especially important because the language is dynamically typed—meaning variables can hold any type of value and can change type at runtime. This flexibility makes JavaScript powerful, but it also means you must be aware of what type of data your variables contain to avoid unexpected results.

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// Variable declarations with different data types let name = "Alice"; // string let age = 30; // number let isStudent = true; // boolean console.log(typeof name); // "string" console.log(typeof age); // "number" console.log(typeof isStudent); // "boolean"
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JavaScript determines the type of a variable based on the value assigned to it. You do not have to declare a variable's type explicitly; instead, JavaScript infers it automatically. For example, if you assign a sequence of characters surrounded by quotes to a variable, JavaScript recognizes it as a string. If you assign a numeric value, it becomes a number. This process is called type inference. Understanding how JavaScript handles data types is crucial because it affects how your code executes. Operations that work with one data type might not work as expected with another, and knowing the type of your variables helps you write reliable, bug-free code.

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bookWhat Are Data Types?

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Before you can write effective JavaScript, you need to understand the concept of data types. In programming, a data type defines the kind of value a variable can hold and the operations that can be performed on that value. Data types help the programming language know how to interpret and handle the data you use in your code. In JavaScript, data types are especially important because the language is dynamically typed—meaning variables can hold any type of value and can change type at runtime. This flexibility makes JavaScript powerful, but it also means you must be aware of what type of data your variables contain to avoid unexpected results.

12345678
// Variable declarations with different data types let name = "Alice"; // string let age = 30; // number let isStudent = true; // boolean console.log(typeof name); // "string" console.log(typeof age); // "number" console.log(typeof isStudent); // "boolean"
copy

JavaScript determines the type of a variable based on the value assigned to it. You do not have to declare a variable's type explicitly; instead, JavaScript infers it automatically. For example, if you assign a sequence of characters surrounded by quotes to a variable, JavaScript recognizes it as a string. If you assign a numeric value, it becomes a number. This process is called type inference. Understanding how JavaScript handles data types is crucial because it affects how your code executes. Operations that work with one data type might not work as expected with another, and knowing the type of your variables helps you write reliable, bug-free code.

question mark

Which of the following best describes the purpose of data types in JavaScript?

Select the correct answer

Все було зрозуміло?

Як ми можемо покращити це?

Дякуємо за ваш відгук!

Секція 1. Розділ 1
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