JavaScript: The Bad Parts

Exploring the quirky and confusing aspects of JavaScript, including its floating point arithmetic, type coercion, semicolon insertion, and more.

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JavaScript: The bad parts

Key Points:

  • Floating Point Arithmetic: JavaScript follows the IEEE Standard for Floating-Point Arithmetic, leading to unexpected results like 0.2 + 0.1 equaling 0.30000000000000004. This isn't a flaw in JavaScript but a characteristic of how numbers are represented in most programming languages and computers.

  • Type Coercion: Being a dynamically and weakly typed language, JavaScript can sometimes perform implicit conversions between different types, which can be confusing. For example, using == can lead to unexpected type coercions, thus the recommendation to use === for strict equality.

  • Automatic Semicolon Insertion (ASI): JavaScript can automatically insert semicolons, but this feature isn't always reliable. It’s better to explicitly insert semicolons to avoid potential issues.

  • Bottom Values (null, undefined, NaN): JavaScript has multiple 'bottom' values representing non-existent or undefined values, which can be confusing and is seen as a design flaw.

  • Increment and Decrement Operators: The use of ++ and -- is seen as unnecessary and can reduce code readability. It’s recommended to use + 1 or – 1” instead for clarity.

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