Create a custom React date picker in 10 minutes

07/14/2019 — 2 Min Read — In React, Datepicker

In this article, I'll show you the easiest way possible to create a date picker using React. We'll be using:

This will be the end result.

I'm assuming that you know basic JavaScript and that you've encountered a little bit of React and hooks before. Other than that, there are no prerequisites.

Let's get started!

Step 1: Install dependencies

First, we need to install our dependencies. Like we mentioned before, we'll use emotion and @datepicker-react/hooks.

yarn add @emotion/core @datepicker-react/hooks

Step 2: Datepicker context

We'll create a Context to share the date picker state and callbacks through the date picker component tree.

Context provides a way to pass data through the component tree without having to pass props down manually at every level.

// datepickerContext.js
import React from "react";
export const datepickerContextDefaultValue = {
  focusedDate: null,
  isDateFocused: () => false,
  isDateSelected: () => false,
  isDateHovered: () => false,
  isDateBlocked: () => false,
  isFirstOrLastSelectedDate: () => false,
  onDateFocus: () => {},
  onDateHover: () => {},
  onDateSelect: () => {}
};
export default React.createContext(datepickerContextDefaultValue);

The upper code creates a Context object, which contains default state and callbacks. When React renders a component that subscribes to this Context object it will read the current context value from the closest matching Provider above it in the tree. If there isn't a matching Provider, then the current Context will read default values.

Step 3: NavButton component

In this step, we'll create a button, which will allow us to navigate through months. A Button component will receive two props, children and onClick callback.

// NavButton.js
/** @jsx jsx */
import { jsx } from "@emotion/core";
export default function NavButton({ children, onClick }) {
  return (
    <button
      type="button"
      onClick={onClick}
      css={{
        border: "1px solid #929598",
        background: "transparent",
        padding: "8px",
        fontSize: "12px"
      }}
    >
      {children}
    </button>
  );
}

Step 4: Datepicker component

This will be our core component, which will contain our date picker logic. Date manipulation isn't the easiest job to do in a JavaScript. That's why people use libraries like moment, date-fns and luxon.

Luckily, we don't have to use any of them, because we use @dapicker-react/hooks, which does all the dirty job for us. We need just to use the right hook and pass the proper arguments.

@dapicker-react/hooks has three exported hooks:

useDatepicker
useMonth
useDay

We can understand from the name, that we will use useDatepicker hook in Datepicker component.

So let's program the Datepicker component.

1. Define state

We need to manage the start and end date, which we can do with the useState hook.

// Datepicker.js
import React, { useState } from "react";
import { START_DATE } from "@datepicker-react/hooks";
function Datepicker() {
  const [state, setState] = useState({
    startDate: null,
    endDate: null,
    focusedInput: START_DATE
  });
  return null
}
export default Datepicker;

We set the initial state value. We have an empty start and end date. We see that we also have focusedInput in the state object, with which we determine or choose the start or end date.

2. useDatepicker hook

We can pass various arguments (see all) to the useDatepicker hook, but we will pass just the required ones. useDatepicker return an object, which includes callbacks and variables, that we need to manage the date picker. Some of them we'll pass to the Context, which we did in step 2.

import React, { useState } from "react";
import { useDatepicker, START_DATE } from "@datepicker-react/hooks";
function Datepicker() {
  const [state, setState] = useState({
    startDate: null,
    endDate: null,
    focusedInput: START_DATE
  });
  const {
    firstDayOfWeek,
    activeMonths,
    isDateSelected,
    isDateHovered,
    isFirstOrLastSelectedDate,
    isDateBlocked,
    isDateFocused,
    focusedDate,
    onDateHover,
    onDateSelect,
    onDateFocus,
    goToPreviousMonths,
    goToNextMonths
  } = useDatepicker({
    startDate: state.startDate,
    endDate: state.endDate,
    focusedInput: state.focusedInput,
    onDatesChange: handleDateChange
  });
  function handleDateChange(data) {
    if (!data.focusedInput) {
      setState({ ...data, focusedInput: START_DATE });
    } else {
      setState(data);
    }
  }
  return null
}
export default Datepicker;

3. Final Datepicker component

/** @jsx jsx */
import { useState } from "react";
import { useDatepicker, START_DATE } from "@datepicker-react/hooks";
import { jsx } from "@emotion/core";
import Month from "./Month";
import NavButton from "./NavButton";
import DatepickerContext from "./datepickerContext";
function Datepicker() {
  const [state, setState] = useState({
    startDate: null,
    endDate: null,
    focusedInput: START_DATE
  });
  const {
    firstDayOfWeek,
    activeMonths,
    isDateSelected,
    isDateHovered,
    isFirstOrLastSelectedDate,
    isDateBlocked,
    isDateFocused,
    focusedDate,
    onDateHover,
    onDateSelect,
    onDateFocus,
    goToPreviousMonths,
    goToNextMonths
  } = useDatepicker({
    startDate: state.startDate,
    endDate: state.endDate,
    focusedInput: state.focusedInput,
    onDatesChange: handleDateChange
  });
  function handleDateChange(data) {
    if (!data.focusedInput) {
      setState({ ...data, focusedInput: START_DATE });
    } else {
      setState(data);
    }
  }
  return (
    <DatepickerContext.Provider
      value={{
        focusedDate,
        isDateFocused,
        isDateSelected,
        isDateHovered,
        isDateBlocked,
        isFirstOrLastSelectedDate,
        onDateSelect,
        onDateFocus,
        onDateHover
      }}
    >
      <div>
        <strong>Focused input: </strong>
        {state.focusedInput}
      </div>
      <div>
        <strong>Start date: </strong>
        {state.startDate && state.startDate.toLocaleString()}
      </div>
      <div>
        <strong>End date: </strong>
        {state.endDate && state.endDate.toLocaleString()}
      </div>
      <NavButton onClick={goToPreviousMonths}>Previous</NavButton>
      <NavButton onClick={goToNextMonths}>Next</NavButton>
      <div
        css={{
          display: "grid",
          margin: "32px 0 0",
          gridTemplateColumns: `repeat(${activeMonths.length}, 300px)`,
          gridGap: "0 64px"
        }}
      >
        {activeMonths.map(month => (
          <Month
            key={`${month.year}-${month.month}`}
            year={month.year}
            month={month.month}
            firstDayOfWeek={firstDayOfWeek}
          />
        ))}
      </div>
    </DatepickerContext.Provider>
  );
}
export default Datepicker;

Step 5: Month component

Probably you see that Month component is included into Datepicker component and it gets three props year, month and firstDayOfWeek. All of these we will pass to the useMonth hook, which will return days of the month, week labels and month label.

/** @jsx jsx */
import { useMonth } from "@datepicker-react/hooks";
import { jsx } from "@emotion/core";
import Day from "./Day";
function Month({ year, month, firstDayOfWeek }) {
  const { days, weekdayLabels, monthLabel } = useMonth({
    year,
    month,
    firstDayOfWeek
  });
  return (
    <div>
      <div css={{ textAlign: "center", margin: "0 0 16px" }}>
        <strong>{monthLabel}</strong>
      </div>
      <div
        css={{
          display: "grid",
          gridTemplateColumns: "repeat(7, 1fr)",
          justifyContent: "center",
          marginBottom: "10px",
          fontSize: "10px"
        }}
      >
        {weekdayLabels.map(dayLabel => (
          <div css={{ textAlign: "center" }} key={dayLabel}>
            {dayLabel}
          </div>
        ))}
      </div>
      <div
        css={{
          display: "grid",
          gridTemplateColumns: "repeat(7, 1fr)",
          justifyContent: "center"
        }}
      >
        {days.map((day, index) => {
          if (typeof day === "object") {
            return (
              <Day
                date={day.date}
                key={day.date.toString()}
                dayLabel={day.dayLabel}
              />
            );
          }
          return <div key={index} />;
        })}
      </div>
    </div>
  );
}
export default Month;

Step 6: Day component

We are close to the finish line, we need just to do the Day component. It will receive date and dayLabel props. We will pass date prop along with callbacks from date picker context (step 2) to the useDay hook.

/** @jsx jsx */
import { useRef, useContext } from "react";
import { useDay } from "@datepicker-react/hooks";
import { jsx } from "@emotion/core";
import DatepickerContext from "./datepickerContext";
function getColor(
  isSelected,
  isSelectedStartOrEnd,
  isWithinHoverRange,
  isDisabled
) {
  return ({
    selectedFirstOrLastColor,
    normalColor,
    selectedColor,
    rangeHoverColor,
    disabledColor
  }) => {
    if (isSelectedStartOrEnd) {
      return selectedFirstOrLastColor;
    } else if (isSelected) {
      return selectedColor;
    } else if (isWithinHoverRange) {
      return rangeHoverColor;
    } else if (isDisabled) {
      return disabledColor;
    } else {
      return normalColor;
    }
  };
}
function Day({ dayLabel, date }) {
  const dayRef = useRef(null);
  const {
    focusedDate,
    isDateFocused,
    isDateSelected,
    isDateHovered,
    isDateBlocked,
    isFirstOrLastSelectedDate,
    onDateSelect,
    onDateFocus,
    onDateHover
  } = useContext(DatepickerContext);
  const {
    isSelected,
    isSelectedStartOrEnd,
    isWithinHoverRange,
    disabledDate,
    onClick,
    onKeyDown,
    onMouseEnter,
    tabIndex
  } = useDay({
    date,
    focusedDate,
    isDateFocused,
    isDateSelected,
    isDateHovered,
    isDateBlocked,
    isFirstOrLastSelectedDate,
    onDateFocus,
    onDateSelect,
    onDateHover,
    dayRef
  });
  if (!dayLabel) {
    return <div />;
  }
  const getColorFn = getColor(
    isSelected,
    isSelectedStartOrEnd,
    isWithinHoverRange,
    disabledDate
  );
  return (
    <button
      onClick={onClick}
      onKeyDown={onKeyDown}
      onMouseEnter={onMouseEnter}
      tabIndex={tabIndex}
      type="button"
      ref={dayRef}
      css={{
        padding: "8px",
        border: 0,
        color: getColorFn({
          selectedFirstOrLastColor: "#FFFFFF",
          normalColor: "#001217",
          selectedColor: "#FFFFFF",
          rangeHoverColor: "#FFFFFF",
          disabledColor: "#808285"
        }),
        background: getColorFn({
          selectedFirstOrLastColor: "#00aeef",
          normalColor: "#FFFFFF",
          selectedColor: "#71c9ed",
          rangeHoverColor: "#71c9ed",
          disabledColor: "#FFFFFF"
        })
      }}
    >
      {dayLabel}
    </button>
  );
}
export default Day;

Congrats! You created a basic date picker component and get a basic understanding of the React context and hooks.

I demonstrate how easy is to create a date picker with @datepicker-react/hooks library. If you want to use internationalizable, accessible, mobile-friendly date picker, you can use a @datepicker-react/styled library.

PreviousTheming React datepicker (@datepicker-react/styled)