mimeTypeToContentType

Summary

Converts a MIME type to a Content-Type header value, adding charset when appropriate.

By default, adds ; charset=utf-8 to text-based MIME types:

• All text/* types (except text/xml)
• All +json suffixed types (RFC 8259 defines JSON as UTF-8)
• application/json, application/javascript

Custom charset registered via import('./define-mime-type.ts').defineMimeType takes precedence over built-in rules.

Note: text/xml is excluded because XML has built-in encoding detection. Per the XML spec, documents without an encoding declaration must be UTF-8 or UTF-16, detectable from byte patterns. Adding an external charset parameter is redundant and can conflict with the document's internal declaration.

Signature

function mimeTypeToContentType(mimeType: string): string;

Example

mimeTypeToContentType("text/html"); // 'text/html; charset=utf-8'
mimeTypeToContentType("application/json"); // 'application/json; charset=utf-8'
mimeTypeToContentType("application/ld+json"); // 'application/ld+json; charset=utf-8'
mimeTypeToContentType("image/png"); // 'image/png'
mimeTypeToContentType("text/xml"); // 'text/xml'

Parameters

mimeType

The MIME type (e.g. "text/css", "image/png")

Returns

The Content-Type value with charset if appropriate