我有兩個功能
async function convertToBase64(file) {
const fileReader = new FileReader();
fileReader.onload = () => {
const srcData = fileReader.result;
console.log('scrData: ', srcData); // result is correct
return srcData;
};
fileReader.readAsDataURL(file);
}
async function addData(values) {
const converted = await convertToBase64(values.file);
console.log(converted); // result undefined
await addDoc(collection(db, 'list'), {
image: converted,
});
}
我嘗試過try...catch、async-await函數，但無論如何都找不到解決方案
convertToBase64()函數不會明確傳回值，因此您提供的程式碼總是會傳回undefined。您可以更改函數，使其傳回一個Promise，一旦resolves " rel="nofollow noreferrer">FileReader 已成功讀取base64 中的文件，並處理任何rejections 或發生的錯誤：const imgFileInput = document.getElementById("img"); imgFileInput.addEventListener("change", addData); function convertToBase64(file) { return new Promise((resolve) => { const fileReader = new FileReader(); fileReader.onload = () => { const srcData = fileReader.result; resolve(srcData); }; fileReader.onerror = (error) => { reject(error); }; fileReader.readAsDataURL(file); }); } async function addData() { try { const imgFile = imgFileInput.files[0]; const converted = await convertToBase64(imgFile); console.log(converted); } catch (error) { console.error("Error while converting to Base64:", error); } }