Get the yesterday date
Subtract one calendar day in UTC.
function yesterday(date) { const d = new Date(date); d.setUTCDate(d.getUTCDate() - 1); return d.toISOString().slice(0, 10); }
Input & expected output
Input
"2026-10-28"Expected output
"2026-10-27"The edge case
Input
"2026-03-01"Expected output
"2026-02-28"Know the limits
- Calendar days, not 24-hour steps.
The function above is the implementation used by the lab. The lab validates JSON types and caps size before execution; include equivalent validation when accepting untrusted input in your application.
Source & maintenance
Based on Get the yesterday date from the original 1loc collection by Nguyen Huu Phuoc. Copyright (c) 2020 phuoc-ng. MIT licensed.
Subtracts a calendar day in UTC. Original MDX retained as inert source evidence.
Maintained by Oveyon. Source commit: 14b481cf60df. Read the license.
Keep exploring
- Compare two dates — Compare validated ISO calendar dates in UTC and return -1, 0 or 1.
- Add AM PM suffix to an hour — Turn an hour from 0 to 23 into a 12-hour label with am or pm.
- Calculate the number of days between two dates — Count whole calendar days between two YYYY-MM-DD dates.