js pdf转base64

function pdfToBase64(file) {
    return new Promise((resolve, reject) => {
        const reader = new FileReader();
        reader.readAsDataURL(file);
        reader.onloadend = () => resolve(reader.result.split(',')[1]);
        reader.onerror = error => reject(error);
    });
}

// 使用方法
const input = document.createElement('input');
input.type = 'file';
input.accept = '.pdf';
input.onchange = async (event) => {
    const file = event.target.files[0];
    try {
        const base64 = await pdfToBase64(file);
        console.log('Base64编码:', base64);
    } catch (error) {
        console.error('转换失败:', error);
    }
};
document.body.appendChild(input);

function pdfToBase64Chunked(file, chunkSize = 1024 * 1024) {
    return new Promise((resolve, reject) => {
        let offset = 0;
        let chunks = [];
        function readChunk() {
            const reader = new FileReader();
            const nextChunk = file.slice(offset, offset + chunkSize);
            reader.readAsArrayBuffer(nextChunk);
            reader.onloadend = (e) => {
                if (e.target.readyState == FileReader.DONE) {
                    chunks.push(new Uint8Array(e.target.result));
                    offset += chunkSize;
                    if (offset < file.size) {
                        readChunk();
                    } else {
                        const blob = new Blob(chunks);
                        const reader = new FileReader();
                        reader.readAsDataURL(blob);
                        reader.onloadend = () => resolve(reader.result.split(',')[1]);
                    }
                }
            };
            reader.onerror = error => reject(error);
        }
        readChunk();
    });
}