gristlabs_grist-core/app/client/widgets/TZAutocomplete.ts

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import {MomentTimezone} from 'app/client/lib/imports';
import {ACIndexImpl} from 'app/client/lib/ACIndex';
import {ACSelectItem, buildACSelect} from 'app/client/lib/ACSelect';
import {testId} from "app/client/ui2018/cssVars";
import {nativeCompare} from 'app/common/gutil';
import {IDisposableOwner, Observable} from 'grainjs';
/**
* Returns the ordered list of offsets for names at time timestamp. See timezoneOptions for details
* on the sorting order.
*/
// exported for testing
export function timezoneOptionsImpl(
timestamp: number, names: string[], moment: MomentTimezone
): ACSelectItem[] {
// What we want is moment(timestamp) but the dynamic import with our compiling settings produces
// "moment is not a function". The following is equivalent, and easier than fixing import setup.
const m = moment.unix(timestamp / 1000);
const options = names.map((value) => ({
cleanText: value.toLowerCase().trim(),
value,
label: `(GMT${m.tz(value).format('Z')}) ${value}`,
// A quick test reveal that it is a bit more efficient (~0.02ms) to get the offset using
// `moment.tz.Zone#parse` than creating a Moment instance for each zone and then getting the
// offset with `moment#utcOffset`.
offset: -moment.tz.zone(value)!.parse(timestamp)
}));
options.sort((a, b) => nativeCompare(a.offset, b.offset) || nativeCompare(a.value, b.value));
return options;
}
/**
* Returns the array of IOptionFull<string> expected by `select` to create the list of timezones
* options. The returned list is sorted based on the current offset (GMT-11:00 before GMT-10:00),
* and then on alphabetical order of the name.
*/
function timezoneOptions(moment: MomentTimezone): ACSelectItem[] {
return timezoneOptionsImpl(Date.now(), moment.tz.names(), moment);
}
/**
* Creates a textbox with an autocomplete dropdown to select a time zone.
* Usage: dom.create(buildTZAutocomplete, momentModule, valueObs, saveCallback)
*/
export function buildTZAutocomplete(
owner: IDisposableOwner,
moment: MomentTimezone,
valueObs: Observable<string>,
save: (value: string) => Promise<void>|void
) {
// Set a large maxResults, since it's sometimes nice to see all supported timezones (there are
// fewer than 1000 in practice).
const acIndex = new ACIndexImpl<ACSelectItem>(timezoneOptions(moment), 1000, true);
// Only save valid time zones. If there is no selected item, we'll auto-select and save only
// when there is a good match.
const saveTZ = (value: string, item: ACSelectItem|undefined) => {
if (!item) {
const results = acIndex.search(value);
if (results.selectIndex >= 0 && results.items.length > 0) {
item = results.items[results.selectIndex];
value = item.value;
}
}
if (!item) { throw new Error("Invalid time zone"); }
if (value !== valueObs.get()) {
return save(value);
}
};
return buildACSelect(owner,
{acIndex, valueObs, save: saveTZ},
testId("tz-autocomplete")
);
}