| |
| /** |
| * Module exports. |
| */ |
| |
| module.exports = weekdayRange; |
| |
| /** |
| * Only the first parameter is mandatory. Either the second, the third, or both |
| * may be left out. |
| * |
| * If only one parameter is present, the function yeilds a true value on the |
| * weekday that the parameter represents. If the string "GMT" is specified as |
| * a second parameter, times are taken to be in GMT, otherwise in local timezone. |
| * |
| * If both wd1 and wd1 are defined, the condition is true if the current weekday |
| * is in between those two weekdays. Bounds are inclusive. If the "GMT" parameter |
| * is specified, times are taken to be in GMT, otherwise the local timezone is |
| * used. |
| * |
| * Valid "weekday strings" are: |
| * |
| * SUN MON TUE WED THU FRI SAT |
| * |
| * Examples: |
| * |
| * ``` js |
| * weekdayRange("MON", "FRI") |
| * true Monday trhough Friday (local timezone). |
| * |
| * weekdayRange("MON", "FRI", "GMT") |
| * same as above, but GMT timezone. |
| * |
| * weekdayRange("SAT") |
| * true on Saturdays local time. |
| * |
| * weekdayRange("SAT", "GMT") |
| * true on Saturdays GMT time. |
| * |
| * weekdayRange("FRI", "MON") |
| * true Friday through Monday (note, order does matter!). |
| * ``` |
| * |
| * |
| * @param {String} wd1 one of the weekday strings. |
| * @param {String} wd2 one of the weekday strings. |
| * @param {String} gmt is either the string: GMT or is left out. |
| * @return {Boolean} |
| */ |
| |
| const dayOrder = { "SUN": 0, "MON": 1, "TUE": 2, "WED": 3, "THU": 4, "FRI": 5, "SAT": 6 }; |
| |
| function weekdayRange (wd1, wd2, gmt) { |
| |
| var useGMTzone = (wd2 == "GMT" || gmt == "GMT"), |
| todaysDay = getTodaysDay(useGMTzone), |
| wd1Index = dayOrder[wd1] || -1, |
| wd2Index = dayOrder[wd2] || -1, |
| result = false; |
| |
| if (wd2Index < 0) { |
| result = (todaysDay == wd1Index); |
| } else { |
| if (wd1Index <= wd2Index) { |
| result = valueInRange(wd1Index, todaysDay, wd2Index); |
| } else { |
| result = valueInRange(wd1Index, todaysDay, 6) || valueInRange(0, todaysDay, wd2Index); |
| } |
| } |
| return result; |
| } |
| |
| function getTodaysDay (gmt) { |
| return (gmt ? (new Date()).getUTCDay() : (new Date()).getDay()); |
| } |
| |
| // start <= value <= finish |
| function valueInRange (start, value, finish) { |
| return (start <= value) && (value <= finish); |
| } |