A simple function that evaluates and produces html from markdown

simple_markdown_parse.js

/**
 * @description A simple function to parse markdown code into HTML
 */

const parseMarkdown = (str) => str.replace(/^# (.*$)/gim, "<h1>$1</h1>")
    .replace(/^## (.*$)/gim, "<h2>$1</h2>")
    .replace(/^### (.*$)/gim, "<h3>$i</h3>")
    .replace(/^#### (.*$)/gim, "<h4>$i</h4>")
    .replace(/^##### (.*$)/gim, "<h5>$i</h5>")
    .replace(/^###### (.*$)/gim, "<h6>$i</h6>")
    .replace(/^\> (.*$)/gim, "<blockquote>$1</blockqoute>")
    .replace(/\*\*(.*)\*\*/gim, '<b>$1</b>')
    .replace(/__(.*)__/g, "<b>$1</b>")
    .replace(/\*(.*)\*/gim, '<i>$1</i>')
    .replace(/_(.*)_/g, "<i>$1</i>")
    .replace(/!\[(.*?)\]\((.*?)\)/gim, "<img alt='$1' src='$2' />")
    .replace(/\[(.*?)\]\((.*?)\)/gim, "<a href='$2'>$1</a>")
    .replace(/\`\`\`([.\s\S\d]*)\`\`\`/g, "<code>$1</code>")
    .replace(/<\s*script\s*[^>]*>[.\s\S\d]*<\s*\/\s*script[^>]*>/g, "")
    .replace(/\n$/gim, '<br />').trim();

const testStr = `
# Hello World
**This is a bold text**
__Spiff__
*Italic Text*
_Italic Text2_
[MIT](./LICENSE.md)
![A face](./pic1.jpg)

> Hello World
\`\`\`
    This is a piece of code
\`\`\`
<><script src="evil.com" > < / script >`;

const testStr2 = `
## FlattenArray
Flatten an array of arrays into one or more. It flexible enough that you can dictate the maximum depth it unveils.

### Example
\`\`\`js
const arr = [
    [1, 2, 3],
    [4, 5, 6],
    7, 8, 9,
    [10, 
        [11,
            [12,
                [13, 14, 15]
            ],
        16,
        ],
        17,
    ],
    18
];

console.log(flattenArr(arr, 3));
// [ 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, [ 13, 14, 15 ], 16, 17, 18 ]

console.log(flattenArr(arr));
/* [
   1,  2,  3,  4,  5,  6,  7,
   8,  9, 10, 11, 12, 13, 14,
  15, 16, 17, 18
] */
\`\`\`

### Author
Spiff Jekey-Green

### License
[MIT](./LICENSE) License
`;

console.log(parseMarkdown(testStr));