17 lines
881 B
JavaScript
17 lines
881 B
JavaScript
'use strict';
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const TYPES = [
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{ ext: 'jpg', test: b => b.length >= 3 && b[0] === 0xff && b[1] === 0xd8 && b[2] === 0xff },
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{ ext: 'png', test: b => b.length >= 8 && b.subarray(0, 8).equals(Buffer.from([137, 80, 78, 71, 13, 10, 26, 10])) },
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{ ext: 'gif', test: b => b.length >= 6 && /^GIF8[79]a$/.test(b.subarray(0, 6).toString('ascii')) },
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{ ext: 'webp', test: b => b.length >= 12 && b.subarray(0, 4).toString('ascii') === 'RIFF' && b.subarray(8, 12).toString('ascii') === 'WEBP' },
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{ ext: 'bmp', test: b => b.length >= 2 && b.subarray(0, 2).toString('ascii') === 'BM' },
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{ ext: 'avif', test: b => b.length >= 12 && b.subarray(4, 12).toString('ascii').includes('ftyp') && /avif|avis/.test(b.subarray(8, 32).toString('ascii')) },
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];
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function imageExtension(buffer) {
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return TYPES.find(type => type.test(buffer))?.ext || null;
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}
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module.exports = { imageExtension };
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