How Does JSON Handle Unicode Characters: Escape Sequences vs. Literal UTF-8?

Character Encoding in JSON: Understanding Unicode Representation

Unicode characters can be encoded in JSON using various formats. One method, which is commonly used by PHP's json_encode function, is the "u" escape sequence. This format represents characters as hexadecimal code points, such as:

"foo": "\u99ac"

This escape sequence is valid JSON and will be interpreted correctly by compliant JSON parsers, resulting in the string "馬".

Why Escape Sequences are Preferred

By default, PHP's json_encode prefers to use escape sequences for non-ASCII characters. While this may not be aesthetically pleasing, it is perfectly valid and does not affect data integrity.

Benefits of Escape Sequences

• Portability: Escape sequences are universally recognized by JSON parsers, ensuring compatibility across platforms and applications.
• Compactness: Escape sequences can be shorter than the equivalent UTF-8 character representation, resulting in smaller JSON payloads.

Enabling Literal Characters

If you prefer to represent Unicode characters without escape sequences, you can specify the JSON_UNESCAPED_UNICODE flag when calling json_encode. This will cause the characters to be output as literal UTF-8:

"foo": "馬"

Conclusion

Both escape sequences and literal characters are valid ways to represent Unicode in JSON. The choice of which method to use depends on specific preferences and requirements.

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