NumberInput.tsx

import React, { useState, useEffect, useRef, forwardRef } from 'react';
import { useMergedRef, assignRef, useOs, clamp } from '@mantine/hooks';
import { DefaultProps, Selectors, useComponentDefaultProps } from '@mantine/styles';
import { TextInput } from '../TextInput';
import { InputStylesNames, InputWrapperStylesNames } from '../Input';
import { getInputMode } from './get-input-mode/get-input-mode';
import { Chevron } from './Chevron';
import useStyles, { CONTROL_SIZES } from './NumberInput.styles';

export type InnerNumberInputStylesNames = Selectors<typeof useStyles>;
export type NumberInputStylesNames =
  | InputStylesNames
  | InputWrapperStylesNames
  | InnerNumberInputStylesNames;

export interface NumberInputHandlers {
  increment(): void;
  decrement(): void;
}

type Formatter = (value: string | undefined) => string;
type Parser = (value: string | undefined) => string | undefined;

export interface NumberInputProps
  extends DefaultProps<NumberInputStylesNames>,
    Omit<
      React.ComponentPropsWithoutRef<typeof TextInput>,
      'onChange' | 'value' | 'classNames' | 'styles' | 'type'
    > {
  /** onChange input handler for controlled variant, note that input event is not exposed. It will return undefined if the input is empty, otherwise it'll return a number */
  onChange?(value: number | undefined): void;

  /** Input value for controlled variant */
  value?: number | undefined;

  /** The decimal separator */
  decimalSeparator?: string;

  /** Maximum possible value */
  max?: number;

  /** Minimal possible value */
  min?: number;

  /** First value if no initial value was set and increment/decrement is triggered using controls or up/down arrows */
  startValue?: number;

  /** Number by which value will be incremented/decremented with controls and up/down arrows */
  step?: number;

  /** Delay before stepping the value. Can be a number of milliseconds or a function that receives the current step count and returns the delay in milliseconds. */
  stepHoldInterval?: number | ((stepCount: number) => number);

  /** Initial delay in milliseconds before stepping the value. */
  stepHoldDelay?: number;

  /** Removes increment/decrement controls */
  hideControls?: boolean;

  /** Amount of digits after the decimal point  */
  precision?: number;

  /** Only works if a precision is given, removes the trailing zeros */
  removePrecisionTrailingZeros?: boolean;

  /** Default value for uncontrolled variant only */
  defaultValue?: number | undefined;

  /** Prevent value clamp on blur */
  noClampOnBlur?: boolean;

  /** Get increment/decrement handlers */
  handlersRef?: React.ForwardedRef<NumberInputHandlers | undefined>;

  /** Formats the number into the input */
  formatter?: Formatter;

  /** Parses the value from formatter, should be used with formatter at the same time */
  parser?: Parser;

  /** Input type, defaults to text */
  type?: 'text' | 'number';
}

const defaultFormatter: Formatter = (value) => value || '';
const defaultParser: Parser = (num) => {
  if (num === '-') {
    return num;
  }

  let tempNum = num;

  if (tempNum[0] === '.') {
    tempNum = `0${num}`;
  }

  const parsedNum = parseFloat(tempNum);

  if (Number.isNaN(parsedNum)) {
    return undefined;
  }

  return num;
};

const CHEVRON_SIZES = {
  xs: 10,
  sm: 14,
  md: 16,
  lg: 18,
  xl: 20,
};

const defaultProps: Partial<NumberInputProps> = {
  step: 1,
  hideControls: false,
  size: 'sm',
  precision: 0,
  noClampOnBlur: false,
  removePrecisionTrailingZeros: true,
  formatter: defaultFormatter,
  parser: defaultParser,
  type: 'text',
};

export const NumberInput = forwardRef<HTMLInputElement, NumberInputProps>((props, ref) => {
  const {
    disabled,
    value,
    onChange,
    decimalSeparator,
    min,
    max,
    startValue,
    step,
    stepHoldInterval,
    stepHoldDelay,
    onBlur,
    onFocus,
    onKeyDown,
    onKeyUp,
    hideControls,
    radius,
    variant,
    precision,
    removePrecisionTrailingZeros,
    defaultValue,
    noClampOnBlur,
    handlersRef,
    classNames,
    styles,
    size,
    rightSection,
    rightSectionWidth,
    formatter,
    parser,
    inputMode,
    unstyled,
    type,
    ...others
  } = useComponentDefaultProps('NumberInput', defaultProps, props);

  const { classes, cx, theme } = useStyles(
    { radius, size },
    { classNames, styles, unstyled, name: 'NumberInput' }
  );

  const [focused, setFocused] = useState(false);
  const [_value, setValue] = useState(
    typeof value === 'number' ? value : typeof defaultValue === 'number' ? defaultValue : undefined
  );
  const finalValue = typeof value === 'number' ? value : _value;
  const [tempValue, setTempValue] = useState(
    typeof finalValue === 'number' ? finalValue.toFixed(precision) : ''
  );
  const inputRef = useRef<HTMLInputElement>();
  const handleValueChange = (val: number | undefined) => {
    if (val !== _value && !Number.isNaN(val)) {
      typeof onChange === 'function' && onChange(val);
      setValue(val);
    }
  };

  const formatNum = (val: string | number = '') => {
    let parsedStr = typeof val === 'number' ? String(val) : val;

    if (decimalSeparator) {
      parsedStr = parsedStr.replace(/\./g, decimalSeparator);
    }

    return formatter(parsedStr);
  };

  const parseNum = (val: string): string | undefined => {
    let num = val;

    if (decimalSeparator) {
      num = num.replace(new RegExp(`\\${decimalSeparator}`, 'g'), '.');
    }

    return parser(num);
  };

  const _min = typeof min === 'number' ? min : -Infinity;
  const _max = typeof max === 'number' ? max : Infinity;

  const incrementRef = useRef<() => void>();
  incrementRef.current = () => {
    if (_value === undefined) {
      handleValueChange(startValue ?? min ?? 0);
      setTempValue(startValue?.toFixed(precision) ?? min?.toFixed(precision) ?? '0');
    } else {
      const result = clamp(_value + step, _min, _max).toFixed(precision);

      handleValueChange(parseFloat(result));
      setTempValue(result);
    }
  };

  const decrementRef = useRef<() => void>();
  decrementRef.current = () => {
    if (_value === undefined) {
      handleValueChange(startValue ?? min ?? 0);
      setTempValue(startValue?.toFixed(precision) ?? min?.toFixed(precision) ?? '0');
    } else {
      const result = clamp(_value - step, _min, _max).toFixed(precision);
      handleValueChange(parseFloat(result));
      setTempValue(result);
    }
  };

  assignRef(handlersRef, { increment: incrementRef.current, decrement: decrementRef.current });

  useEffect(() => {
    if (typeof value === 'number' && !focused) {
      setValue(value);
      setTempValue(value.toFixed(precision));
    }
    if (defaultValue === undefined && value === undefined && !focused) {
      setValue(value);
      setTempValue('');
    }
  }, [value]);

  const shouldUseStepInterval = stepHoldDelay !== undefined && stepHoldInterval !== undefined;
  const onStepTimeoutRef = useRef<number>(null);
  const stepCountRef = useRef<number>(0);

  const onStepDone = () => {
    if (onStepTimeoutRef.current) {
      window.clearTimeout(onStepTimeoutRef.current);
    }
    onStepTimeoutRef.current = null;
    stepCountRef.current = 0;
  };

  const onStepHandleChange = (isIncrement: boolean) => {
    if (isIncrement) {
      incrementRef.current();
    } else {
      decrementRef.current();
    }
    stepCountRef.current += 1;
  };

  const onStepLoop = (isIncrement: boolean) => {
    onStepHandleChange(isIncrement);

    if (shouldUseStepInterval) {
      const interval =
        typeof stepHoldInterval === 'number'
          ? stepHoldInterval
          : stepHoldInterval(stepCountRef.current);
      onStepTimeoutRef.current = window.setTimeout(() => onStepLoop(isIncrement), interval);
    }
  };

  const onStep = (
    event: React.MouseEvent<HTMLElement> | React.KeyboardEvent<HTMLElement>,
    isIncrement: boolean
  ) => {
    event.preventDefault();
    inputRef.current.focus();
    onStepHandleChange(isIncrement);
    if (shouldUseStepInterval) {
      onStepTimeoutRef.current = window.setTimeout(() => onStepLoop(isIncrement), stepHoldDelay);
    }
  };

  useEffect(() => {
    onStepDone();
    return onStepDone;
  }, []);

  const controls = (
    <div className={classes.rightSection}>
      <button
        type="button"
        tabIndex={-1}
        aria-hidden
        disabled={finalValue >= max}
        className={cx(classes.control, classes.controlUp)}
        onPointerDown={(event) => {
          onStep(event, true);
        }}
        onPointerUp={onStepDone}
        onPointerLeave={onStepDone}
      >
        <Chevron size={theme.fn.size({ size, sizes: CHEVRON_SIZES })} direction="up" />
      </button>
      <button
        type="button"
        tabIndex={-1}
        aria-hidden
        disabled={finalValue <= min}
        className={cx(classes.control, classes.controlDown)}
        onPointerDown={(event) => {
          onStep(event, false);
        }}
        onPointerUp={onStepDone}
        onPointerLeave={onStepDone}
      >
        <Chevron size={theme.fn.size({ size, sizes: CHEVRON_SIZES })} direction="down" />
      </button>
    </div>
  );

  const handleChange = (event: React.ChangeEvent<HTMLInputElement>) => {
    const evt = event.nativeEvent as InputEvent;
    if (evt.isComposing) {
      return;
    }

    const val = event.target.value;
    const parsed = parseNum(val);

    setTempValue(parsed);

    if (val === '' || val === '-') {
      handleValueChange(undefined);
    } else {
      val.trim() !== '' && !Number.isNaN(parsed) && handleValueChange(parseFloat(parsed));
    }
  };

  const handleBlur = (event: React.FocusEvent<HTMLInputElement>) => {
    if (event.target.value === '') {
      setTempValue('');
      handleValueChange(undefined);
    } else {
      let newNumber = event.target.value;

      if (newNumber[0] === `${decimalSeparator}` || newNumber[0] === '.') {
        newNumber = `0${newNumber}`;
      }

      const parsedVal = parseNum(newNumber);
      const val = clamp(parseFloat(parsedVal), _min, _max);

      if (!Number.isNaN(val)) {
        if (!noClampOnBlur) {
          if (removePrecisionTrailingZeros) {
            const valNoZeros = val
              .toFixed(precision)
              .replace(new RegExp(`[0]{0,${precision}}$`), '');

            if (valNoZeros.endsWith(decimalSeparator) || valNoZeros.endsWith('.')) {
              setTempValue(valNoZeros.slice(0, -1));
              handleValueChange(parseFloat(valNoZeros.slice(0, -1)));
            } else {
              setTempValue(valNoZeros);
              handleValueChange(parseFloat(valNoZeros));
            }
          } else {
            setTempValue(val.toFixed(precision));
            handleValueChange(parseFloat(val.toFixed(precision)));
          }
        }
      } else {
        setTempValue(finalValue?.toFixed(precision) ?? '');
      }
    }

    setFocused(false);
    typeof onBlur === 'function' && onBlur(event);
  };

  const handleFocus = (event: React.FocusEvent<HTMLInputElement>) => {
    setFocused(true);
    typeof onFocus === 'function' && onFocus(event);
  };

  const handleKeyDown = (event: React.KeyboardEvent<HTMLInputElement>) => {
    typeof onKeyDown === 'function' && onKeyDown(event);
    if (
      event.repeat &&
      shouldUseStepInterval &&
      (event.key === 'ArrowUp' || event.key === 'ArrowDown')
    ) {
      event.preventDefault();
      return;
    }

    if (event.key === 'ArrowUp') {
      onStep(event, true);
    } else if (event.key === 'ArrowDown') {
      onStep(event, false);
    }
  };

  const handleKeyUp = (event: React.KeyboardEvent<HTMLInputElement>) => {
    typeof onKeyUp === 'function' && onKeyUp(event);
    if (event.key === 'ArrowUp' || event.key === 'ArrowDown') {
      onStepDone();
    }
  };

  return (
    <TextInput
      {...others}
      type={type}
      variant={variant}
      value={formatNum(tempValue)}
      disabled={disabled}
      ref={useMergedRef(inputRef, ref)}
      onChange={handleChange}
      onBlur={handleBlur}
      onFocus={handleFocus}
      onKeyDown={handleKeyDown}
      onKeyUp={handleKeyUp}
      rightSection={
        rightSection || (disabled || hideControls || variant === 'unstyled' ? null : controls)
      }
      rightSectionWidth={rightSectionWidth || theme.fn.size({ size, sizes: CONTROL_SIZES }) + 1}
      radius={radius}
      max={max}
      min={min}
      step={step}
      size={size}
      styles={styles}
      classNames={classNames}
      inputMode={inputMode || getInputMode(step, precision, useOs())}
      __staticSelector="NumberInput"
      unstyled={unstyled}
    />
  );
});

NumberInput.displayName = '@mantine/core/NumberInput';