// 1. 粘贴你的原始 JSON 字符串
let raw = {
"10": { "upgrade": 0 },
"15": { "upgrade": 3 },
"20": { "upgrade": 4 }
};
// 2. 解析为对象
let data = JSON.parse(raw);
// 3. 批量处理 upgrade 字段
for (let k in data) {
if (data[k].upgrade !== undefined) {
data[k].upgrade = Math.floor(data[k].upgrade / 2); // 向下取整
}
}
// 4. 输出新 JSON 字符串
console.log(JSON.stringify(data, null, 2));