@mui/x-date-pickers/internals/hooks/useValueWithTimezone.js

The community edition of the Date and Time Picker components (MUI X).

import * as React from 'react';
import useEventCallback from '@mui/utils/useEventCallback';
import useControlled from '@mui/utils/useControlled';
import { useUtils } from "./useUtils.js";
/**
 * Hooks making sure that:
 * - The value returned by `onChange` always have the timezone of `props.value` or `props.defaultValue` if defined
 * - The value rendered is always the one from `props.timezone` if defined
 */
export const useValueWithTimezone = ({
  timezone: timezoneProp,
  value: valueProp,
  defaultValue,
  referenceDate,
  onChange,
  valueManager
}) => {
  const utils = useUtils();
  const firstDefaultValue = React.useRef(defaultValue);
  const inputValue = valueProp ?? firstDefaultValue.current ?? valueManager.emptyValue;
  const inputTimezone = React.useMemo(() => valueManager.getTimezone(utils, inputValue), [utils, valueManager, inputValue]);
  const setInputTimezone = useEventCallback(newValue => {
    if (inputTimezone == null) {
      return newValue;
    }
    return valueManager.setTimezone(utils, inputTimezone, newValue);
  });
  let timezoneToRender;
  if (timezoneProp) {
    timezoneToRender = timezoneProp;
  } else if (inputTimezone) {
    timezoneToRender = inputTimezone;
  } else if (referenceDate) {
    timezoneToRender = utils.getTimezone(referenceDate);
  } else {
    timezoneToRender = 'default';
  }
  const valueWithTimezoneToRender = React.useMemo(() => valueManager.setTimezone(utils, timezoneToRender, inputValue), [valueManager, utils, timezoneToRender, inputValue]);
  const handleValueChange = useEventCallback((newValue, ...otherParams) => {
    const newValueWithInputTimezone = setInputTimezone(newValue);
    onChange?.(newValueWithInputTimezone, ...otherParams);
  });
  return {
    value: valueWithTimezoneToRender,
    handleValueChange,
    timezone: timezoneToRender
  };
};

/**
 * Wrapper around `useControlled` and `useValueWithTimezone`
 */
export const useControlledValueWithTimezone = ({
  name,
  timezone: timezoneProp,
  value: valueProp,
  defaultValue,
  referenceDate,
  onChange: onChangeProp,
  valueManager
}) => {
  const [valueWithInputTimezone, setValue] = useControlled({
    name,
    state: 'value',
    controlled: valueProp,
    default: defaultValue ?? valueManager.emptyValue
  });
  const onChange = useEventCallback((newValue, ...otherParams) => {
    setValue(newValue);
    onChangeProp?.(newValue, ...otherParams);
  });
  return useValueWithTimezone({
    timezone: timezoneProp,
    value: valueWithInputTimezone,
    defaultValue: undefined,
    referenceDate,
    onChange,
    valueManager
  });
};