Go-Time
GoTime is a simple but powerful library and syntax for defining times when you desire something to be active, and test dates against that definition.
.'`~~~~~~~~~~~`'.
( .'11 12 1'. )
| :10 \| 2: |
| :9 @ 3: |
| :8 4; |
'. '..7 6 5..' .'
~-------------~
GoTime Syntax
A GoTime definition is a series of test statements, each following this pattern: {part}{operator}{value}
Part
The first section of a test is the part, and it can be one of the following:
| Part code | Meaning |
|---|---|
y |
Year. i.e. 2021 |
m |
Month. 1 - 12 or Jan or January, etc. |
woy |
Week of the Year. 1 - 53 |
wom |
Week of the Month. 1 - 5 |
doy |
Day of the Year. 1 - 365 |
dom |
Day of the Month. 1 - 31 |
dow |
Day of the Week. 1 - 7 or Monday or Mon, etc. Monday is 1. |
time |
Time of Day. 00:00 - 23:59 must have hours : minutes |
datetime |
A complete date time value like yyyy-mm-dd hh:mm:ss
|
Operator
The second section of a GoTime test is the operator.
| Operator | Meaning |
|---|---|
= |
Equals |
<= |
Less than or equal |
>= |
Greater than or equal |
< |
Greater than |
> |
Less than |
Value
The third section of a GoTime test is the value. Valid values depend on the part used in the test. For example, m=2022 is invalid because the m (Month) part is being used, and 2022 isn't a valid Month.
This section can declare a single value, a series of comma separated values, or a span of values with a minimum (inclusive) and maximum (exclusive) separated by a dash or pipe. Only the equals operator can be used with the comma separated values or span syntax; it doesn't make sense to be less than a span or a list of values, for example.
Multiple Statements
A GoTime definition needs at least one test statement, but can include multiple tests separated by a semicolon. Tests using the same part are OR'd together, so if any one is true, the part test passes. For the entire definition to evaluate to true, a the input Date must pass every part. See the exmaples below.
GoTime Examples
Here are some example definitions
| Definition Syntax | Meaning |
|---|---|
M=Oct; DoM>=24 |
Halloween week. The last 7 days of October. |
DoM<7; DoW=Sat,Sun |
The first weekend of the month. (Might only be one Sunday!) |
Time=00:00-01:00; Time=12:00-13:00 |
Midnight hour or noon hour |
Datetime>2022-04-20 |
After a specific point in time |
Datetime=2022-03-20 13:00:00|2022-03-22 05:30:00 |
Between two absolute points in time (separate by pipe symbol; only escaped for markdown) |
GoTime Usage
const firstWeekend = new GoTime('DoM<7; DoW=Sat,Sun')
const now = new Date()
if (firstWeekend.test(now)) {
// Do something here
}