JavaScript日期转换返回旧日期，疑与第三方API返回值相关

Hey there! Let's break down exactly what's going on here and how to fix it:

First off, this isn't an API issue—it's a mismatch in timestamp units between the API and JavaScript's Date function:

• JavaScript's Date constructor expects a millisecond-level timestamp (count of milliseconds since January 1, 1970 UTC)
• The value 1521441000 your API returns is a second-level timestamp (count of seconds since that same epoch). When you pass this directly to Date, it only accounts for ~17 days of time since 1970, hence the incorrect early 1970s date.

Just multiply the API's timestamp by 1000 to convert it to milliseconds, and JavaScript will parse it correctly:

const apiTimestamp = 1521441000;
const correctDate = new Date(apiTimestamp * 1000);
console.log(correctDate.toString()); // Will output something like "Wed Mar 21 2018 ..." which matches your 2018 filter

To double-check the API is working as intended:

• Plug the timestamp 1521441000 into a timestamp converter (make sure to select "seconds" as the unit) — it should map to a date in March/April 2018
• Check the API's documentation to confirm it explicitly returns second-level timestamps (this is a common standard for backend APIs, since it's more compact than milliseconds)

内容的提问来源于stack exchange，提问作者Jyothish Bhaskaran