js校验base64位图片

function isValidBase64Image(base64String) {
    // 检查Base64字符串格式
    const base64Regex = /^data:image\/(png|jpg|jpeg|gif);base64,/;
    if (!base64Regex.test(base64String)) {
        return false;
    }

    // 提取Base64数据部分
    const base64Data = base64String.split(',')[1];

    try {
        // 解码Base64数据
        const decodedData = atob(base64Data);
        const uint8Array = new Uint8Array(decodedData.length);

        for (let i = 0; i < decodedData.length; i++) {
            uint8Array[i] = decodedData.charCodeAt(i);
        }

        // 创建Blob对象
        const blob = new Blob([uint8Array], { type: 'image/png' });

        // 创建Image对象并加载图片
        const img = new Image();
        img.src = URL.createObjectURL(blob);

        return new Promise((resolve, reject) => {
            img.onload = () => resolve(true);
            img.onerror = () => resolve(false);
        });
    } catch (error) {
        return false;
    }
}

// 使用示例
const base64Image = "data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAUA...";
isValidBase64Image(base64Image).then(isValid => {
    console.log("Is valid Base64 image:", isValid);
});