the-forest/client/node_modules/data-uri-to-buffer/dist/index.js

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2024-09-17 20:35:18 -04:00
/**
* Returns a `Buffer` instance from the given data URI `uri`.
*
* @param {String} uri Data URI to turn into a Buffer instance
* @returns {Buffer} Buffer instance from Data URI
* @api public
*/
export function dataUriToBuffer(uri) {
if (!/^data:/i.test(uri)) {
throw new TypeError('`uri` does not appear to be a Data URI (must begin with "data:")');
}
// strip newlines
uri = uri.replace(/\r?\n/g, '');
// split the URI up into the "metadata" and the "data" portions
const firstComma = uri.indexOf(',');
if (firstComma === -1 || firstComma <= 4) {
throw new TypeError('malformed data: URI');
}
// remove the "data:" scheme and parse the metadata
const meta = uri.substring(5, firstComma).split(';');
let charset = '';
let base64 = false;
const type = meta[0] || 'text/plain';
let typeFull = type;
for (let i = 1; i < meta.length; i++) {
if (meta[i] === 'base64') {
base64 = true;
}
else if (meta[i]) {
typeFull += `;${meta[i]}`;
if (meta[i].indexOf('charset=') === 0) {
charset = meta[i].substring(8);
}
}
}
// defaults to US-ASCII only if type is not provided
if (!meta[0] && !charset.length) {
typeFull += ';charset=US-ASCII';
charset = 'US-ASCII';
}
// get the encoded data portion and decode URI-encoded chars
const encoding = base64 ? 'base64' : 'ascii';
const data = unescape(uri.substring(firstComma + 1));
const buffer = Buffer.from(data, encoding);
// set `.type` and `.typeFull` properties to MIME type
buffer.type = type;
buffer.typeFull = typeFull;
// set the `.charset` property
buffer.charset = charset;
return buffer;
}
export default dataUriToBuffer;
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