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metamask-extension/ui/helpers/utils/export-utils.js
Nicholas Ellul 51cad751de Add improved downloading logic when exporting state logs (#19872)
* Add improved downloading logic when exporting state logs

* Make test for state logs download only apply to firefox

* Remove eslint override

* Add file extension to test

* Move make jest global.Blob accessible to window
2023-07-27 15:45:51 -02:30

96 lines
2.7 KiB
JavaScript

/**
* @enum { string }
*/
export const ExportableContentType = {
JSON: 'application/json',
TXT: 'text/plain',
};
/**
* @enum { string }
*/
const ExtensionForContentType = {
[ExportableContentType.JSON]: '.json',
[ExportableContentType.TXT]: '.txt',
};
/**
* Export data as a file.
*
* @param {string} filename - The name of the file to export.
* @param {string} data - The data to export.
* @param {ExportableContentType} contentType - The content type of the file to export.
*/
export async function exportAsFile(filename, data, contentType) {
if (!ExtensionForContentType[contentType]) {
throw new Error(`Unsupported file type: ${contentType}`);
}
if (supportsShowSaveFilePicker()) {
// Preferred method for downloads
await saveFileUsingFilePicker(filename, data, contentType);
} else {
saveFileUsingDataUri(filename, data, contentType);
}
}
/**
* Notes if the browser supports the File System Access API.
*
* @returns {boolean}
*/
function supportsShowSaveFilePicker() {
return (
typeof window !== 'undefined' &&
typeof window.showSaveFilePicker !== 'undefined' &&
typeof window.Blob !== 'undefined'
);
}
/**
* Saves a file using the File System Access API.
*
* @param {string} filename - The name of the file to export.
* @param {string} data - The data to export.
* @param {ExportableContentType} contentType - The content type of the file to export.
* @returns {Promise<void>}
*/
async function saveFileUsingFilePicker(filename, data, contentType) {
const blob = new window.Blob([data], { contentType });
const fileExtension = ExtensionForContentType[contentType];
const handle = await window.showSaveFilePicker({
suggestedName: filename,
types: [
{
description: filename,
accept: {
[contentType]: [fileExtension],
},
},
],
});
const writable = await handle.createWritable();
await writable.write(blob);
await writable.close();
}
/**
* Saves a file using a data URI.
* This is a fallback for browsers that do not support the File System Access API.
* This method is less preferred because it requires the entire file to be encoded in a data URI.
*
* @param {string} filename - The name of the file to export.
* @param {string} data - The data to export.
* @param {ExportableContentType} contentType - The content type of the file to export.
*/
function saveFileUsingDataUri(filename, data, contentType) {
const b64 = Buffer.from(data, 'utf8').toString('base64');
const elem = document.createElement('a');
elem.href = `data:${contentType};Base64,${b64}`;
elem.download = filename;
document.body.appendChild(elem);
elem.click();
document.body.removeChild(elem);
}