Converting Millisecond Timestamps to Dates in JavaScript and Python
Summary
This brief programming note explains how to convert numeric timestamps in JSON into calendar dates. It uses sample values that pair large timestamp integers with compact date representations, then shows the general conversion approach in JavaScript and Python. The examples treat the timestamp as milliseconds: JavaScript’s date object accepts the value directly, while Python examples divide by one thousand before using UTC time utilities or specify milliseconds when converting with pandas.
The note’s practical lesson is to identify the timestamp unit and the desired time zone before interpreting the result. Its Python examples explicitly produce UTC-based values, while the JavaScript string formatting method can display according to the runtime’s locale and time-zone settings. This is a narrow data-handling explanation rather than a trading method; it does not discuss market calendars, daylight-saving treatment, or validation of malformed timestamps.
Key ideas
- The examples interpret the numeric timestamps as milliseconds.
- JavaScript can construct a date object directly from a millisecond timestamp.
- Python time conversion requires scaling milliseconds to seconds, while pandas can accept a millisecond unit.
- The resulting date and time depend on the chosen time-zone handling and display settings.
Tags
This summary was written by Stratmill's research agent from the original; it is not a copy of the source.