melt/dist/utils/file.js

The next generation of Melt UI. Built for Svelte 5.

/**
 * Convert a blob to a binary string
 *
 * The blob can optionnaly be sliced with the slice arguments
 *
 * @version 1.0.0
 * @since   1.0.0
 * @param   {Blob}  blob Blob to convert and optionnally sample
 * @param   {Number}  chunk Size in bytes to slice blob
 * @return  {Promise<string>}       Binary data as a string
 */
export function blobToBinaryString(blob, chunk) {
    return new Promise((resolve, reject) => {
        const reader = new FileReader();
        const s = chunk ? Math.min(chunk, blob.size) : blob.size;
        const b = blob.slice(0, s);
        reader.onload = () => resolve(reader.result); // Type assertion
        reader.onerror = reject;
        reader.readAsBinaryString(b);
    });
}
/**
 * Convert a blob to an ArrayBuffer
 *
 * The blob can optionnally be sliced with the `size`argument
 *
 * @version 1.0.0
 * @since   1.0.0
 * @param   {Blob}  blob Blob
 * @param   {Number}  chunk Size in bytes to slice blob
 * @return  {Promise<ArrayBuffer>}       Binary data as a buffer
 */
export function blobToArrayBuffer(blob, chunk) {
    return new Promise((resolve, reject) => {
        const reader = new FileReader();
        const s = chunk ? Math.min(chunk, blob.size) : blob.size;
        const b = blob.slice(0, s);
        reader.onload = () => resolve(reader.result); // Type assertion
        reader.onerror = reject;
        reader.readAsArrayBuffer(b);
    });
}
/**
 * Compares two buffers byte to byte
 *
 * @version 1.0.0
 * @since   1.0.0
 * @param   {ArrayBuffer}  buf1          First buffer
 * @param   {ArrayBuffer}  buf2          Second buffer
 * @return  {Boolean}           `true` if buffers are equal
 */
export function compareBuffers(buf1, buf2) {
    if (buf1 === buf2)
        return true;
    if (buf1.byteLength !== buf2.byteLength)
        return false;
    const d1 = new DataView(buf1), d2 = new DataView(buf2);
    let i = buf1.byteLength;
    while (i--) {
        /* istanbul ignore else */
        if (d1.getUint8(i) !== d2.getUint8(i))
            return false;
    }
    return true;
}
/**
 * Compares two File objects by their content using chunking.
 *
 * @param {File} file1 The first File object.
 * @param {File} file2 The second File object.
 * @param {number} [chunkSize=1024 * 1024] The chunk size in bytes.  Defaults
 *  to 1MB.
 * @returns {Promise<boolean>} A promise that resolves to true if the files
 *  have the same content, false otherwise.
 */
export async function areFilesEqual(file1, file2, chunkSize = 1024 * 1024) {
    if (file1.size !== file2.size) {
        return false; // Optimization: Different sizes mean different content
    }
    let offset = 0;
    while (offset < file1.size) {
        const s = Math.min(chunkSize, file1.size - offset); // Correct slice size
        const b1 = file1.slice(offset, offset + s);
        const b2 = file2.slice(offset, offset + s);
        const chunk1 = await blobToArrayBuffer(b1, chunkSize);
        const chunk2 = await blobToArrayBuffer(b2, chunkSize);
        if (!compareBuffers(chunk1, chunk2)) {
            return false;
        }
        offset += chunkSize;
    }
    return true;
}