120 lines
3.4 KiB
TypeScript
120 lines
3.4 KiB
TypeScript
import { extension as getExtensionFromMimeType, extension as getMimeTypeFromExtension } from 'mime-types';
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import type { MaybeRef, Ref } from 'vue';
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import _ from 'lodash';
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import { get } from '@vueuse/core';
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export {
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getMimeTypeFromBase64,
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getMimeTypeFromExtension, getExtensionFromMimeType,
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useDownloadFileFromBase64, useDownloadFileFromBase64Refs,
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previewImageFromBase64,
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};
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const commonMimeTypesSignatures = {
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'JVBERi0': 'application/pdf',
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'R0lGODdh': 'image/gif',
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'R0lGODlh': 'image/gif',
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'iVBORw0KGgo': 'image/png',
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'/9j/': 'image/jpg',
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};
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function getMimeTypeFromBase64({ base64String }: { base64String: string }) {
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const [,mimeTypeFromBase64] = base64String.match(/data:(.*?);base64/i) ?? [];
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if (mimeTypeFromBase64) {
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return { mimeType: mimeTypeFromBase64 };
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}
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const inferredMimeType = _.find(commonMimeTypesSignatures, (_mimeType, signature) => base64String.startsWith(signature));
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if (inferredMimeType) {
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return { mimeType: inferredMimeType };
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}
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return { mimeType: undefined };
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}
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function getFileExtensionFromMimeType({
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mimeType,
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defaultExtension = 'txt',
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}: {
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mimeType: string | undefined
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defaultExtension?: string
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}) {
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if (mimeType) {
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return getExtensionFromMimeType(mimeType) ?? defaultExtension;
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}
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return defaultExtension;
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}
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function downloadFromBase64({ sourceValue, filename, extension, fileMimeType }:
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{ sourceValue: string; filename?: string; extension?: string; fileMimeType?: string }) {
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if (sourceValue === '') {
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throw new Error('Base64 string is empty');
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}
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const defaultExtension = extension ?? 'txt';
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const { mimeType } = getMimeTypeFromBase64({ base64String: sourceValue });
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let base64String = sourceValue;
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if (!mimeType) {
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const targetMimeType = fileMimeType ?? getMimeTypeFromExtension(defaultExtension);
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base64String = `data:${targetMimeType};base64,${sourceValue}`;
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}
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const cleanExtension = extension ?? getFileExtensionFromMimeType(
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{ mimeType, defaultExtension });
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let cleanFileName = filename ?? `file.${cleanExtension}`;
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if (extension && !cleanFileName.endsWith(`.${extension}`)) {
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cleanFileName = `${cleanFileName}.${cleanExtension}`;
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}
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const a = document.createElement('a');
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a.href = base64String;
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a.download = cleanFileName;
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a.click();
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}
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function useDownloadFileFromBase64(
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{ source, filename, extension }:
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{ source: MaybeRef<string>; filename?: MaybeRef<string>; extension?: MaybeRef<string> }) {
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return {
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download() {
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downloadFromBase64({ sourceValue: get(source), filename: get(filename), extension: get(extension) });
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},
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};
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}
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function previewImageFromBase64(base64String: string): HTMLImageElement {
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if (base64String === '') {
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throw new Error('Base64 string is empty');
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}
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const img = document.createElement('img');
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img.src = base64String;
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const container = document.createElement('div');
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container.appendChild(img);
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const previewContainer = document.getElementById('previewContainer');
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if (previewContainer) {
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previewContainer.innerHTML = '';
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previewContainer.appendChild(container);
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}
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else {
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throw new Error('Preview container element not found');
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}
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return img;
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}
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function useDownloadFileFromBase64Refs(
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{ source, filename, extension }:
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{ source: Ref<string>; filename?: Ref<string>; extension?: Ref<string> }) {
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return {
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download() {
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downloadFromBase64({ sourceValue: source.value, filename: filename?.value, extension: extension?.value });
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},
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};
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}
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