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