Unescaped HTML entities in JSX: react/no-unescaped-entities

The error related to unescaped HTML entities in JSX occurs because certain characters have special meanings in HTML and JSX, and when they are used directly in your JSX code without being properly escaped, they can cause unintended rendering or behavior.

Why This Error Occurs:

Special Characters in HTML/JSX:
- Characters like >, <, ", ', and { have special meanings in HTML and JSX:
  - < and > are used to define HTML tags.
  - { is used to insert JavaScript expressions in JSX.
  - ", ', and } are also used in various contexts within JSX.
- If these characters are used directly in JSX without being escaped, JSX might misinterpret them as part of the syntax rather than as literal characters.
JSX Parsing:
- JSX is essentially a syntax extension for JavaScript, and it gets converted into regular JavaScript before being rendered by the browser. If the parser encounters these special characters in the wrong context, it might misinterpret the code, leading to errors or incorrect rendering.
- For example, if you accidentally leave a > inside a JSX element without escaping it, the parser might think you're closing a tag when you're not, leading to unexpected results.

Example of the Error:

Let's consider the following JSX code:

jsxCopy code<div> 5 > 3 </div>

In this example:

The > symbol is not escaped.
The JSX parser might misinterpret the > as part of the syntax rather than as a literal "greater than" sign.

To fix this, you need to escape the >:

jsxCopy code<div> 5 &gt; 3 </div>

How the `react/no-unescaped-entities` Rule Helps:

The react/no-unescaped-entities rule in ESLint is designed to catch these issues during development:

It prevents you from accidentally including unescaped special characters in your JSX.
By enforcing the use of escaped entities, it ensures that your code will render correctly in the browser.

The react/no-unescaped-entities rule ensures that characters like >, ", ', and } are properly escaped. Here’s how you can correctly escape these characters:

Replace > with >
Replace " with " or "
Replace ' with ' or '
Replace } with }

Alternatively, you can include the character within curly braces:

jsxCopy code<p>{'>'}</p>

This method ensures that React interprets the character correctly.

✅ Correct vs. Incorrect Usage

Incorrect:

jsxCopy code<p> > Start Your Journey</p>

Correct:

jsxCopy code<p> &gt; Start Your Journey</p>
<p>{'>'} Start Your Journey</p>

⚙️ Customizing the Rule

You can also customize the rule to specify which characters should be escaped:

jsonCopy code"react/no-unescaped-entities": ["error", {"forbid": [">", "'"]}],

Or provide alternative escape sequences:

jsonCopy code"react/no-unescaped-entities": ["error", {
  "forbid": [{
    "char": ">",
    "alternatives": ["&gt;"]
  }, {
    "char": "'",
    "alternatives": ["&apos;"]
  }]
}],

This allows you to tailor the rule to fit your project’s specific needs.