MIMEType

MIME Type string parser that tries to conform to the WHATWG MIME Sniff spec.

API

The MIMEType class consists of:

• constructor(string): takes a string representing a MIME type. This sends the string to the parser. If the string is non-conforming, it throws a TypeError errors.
• .essense property: the "type", "/", and "subtype" normalized to lower case. For example: "text/plain".
• .type: the primary type of the string. E.g., "application", "text", or "image".
• .subtype: The subtype. So, like, "plain" in "text/plain".
• .parameters: a Map consisting of the parameters that were passed, normalized per spec.
• .toString(): stringifier gives you back the MIME type in canonical form.

Exported utilty methods

• isValidMimeType(string) - returns boolean, checks if a MIME type is valid by parsing it.
• parseMimeType(string) - returns an object { type: string, subtype: string, params: object }.

Examples

Creating and parsing

1// As a class
2import { MIMEType } from "MIMEType";
3// Or utility functions
4import { isValidMimeType, parseMimeType } from "MIMEType";
5
6const mimetype = new MIMEType("text/html; charset=UTF-8");
7
8// This throws
9try {
10  new MIMEType("not valid");
11} catch (err) {
12  // nice try...
13}

Accessing different parts

1import { MIMEType } from "MIMEType";
2const mimetype = new MIMEType("text/html; charset=UTF-8");
3console.log(mimetype.essense); // text/html
4console.log(mimetype.type) // text
5console.log(mimetype.subtype) // html

Parameters

Parameters is just a regular JavaScript Map, so:

1import { MIMEType } from "MIMEType";
2const mimetype = new MIMEType("text/html; charset=UTF-8");
3
4mimetype.parameters.has("charset"); // true
5
6for(const [key, value] of mimetype.parameters) {
7  console.log(key, value);
8}