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import * as _ from 'lodash';
import * as React from 'react';
import { ColorOption } from '../style/theme';
import { util } from '../util/util';
import { Input } from './ui';
export enum ScalingInputPhase {
Start,
Scaling,
End,
}
export interface ScalingInputProps {
startWidthCh: number;
endWidthCh: number;
maxFontSizePx: number;
value?: string;
onChange: (event: React.ChangeEvent<HTMLInputElement>) => void;
onFontSizeChange: (fontSizePx: number) => void;
fontColor?: ColorOption;
placeholder?: string;
maxLength?: number;
}
export interface ScalingInputState {
fixedWidthInPxIfExists?: number;
}
export interface ScalingInputSnapshot {
inputWidthPx: number;
}
// This is a magic number that was determined experimentally.
const percentageToReduceByPerCharacter = 0.18;
export class ScalingInput extends React.Component<ScalingInputProps, ScalingInputState> {
public static defaultProps = {
onChange: util.boundNoop,
onFontSizeChange: util.boundNoop,
maxLength: 9,
};
public state = {
fixedWidthInPxIfExists: undefined,
};
private readonly _inputRef = React.createRef();
public static getPhase(startWidthCh: number, endWidthCh: number, value?: string): ScalingInputPhase {
if (_.isUndefined(value) || value.length <= startWidthCh) {
return ScalingInputPhase.Start;
}
if (value.length > startWidthCh && value.length <= endWidthCh) {
return ScalingInputPhase.Scaling;
}
return ScalingInputPhase.End;
}
public static getPhaseFromProps(props: ScalingInputProps): ScalingInputPhase {
const { value, startWidthCh, endWidthCh } = props;
return ScalingInput.getPhase(startWidthCh, endWidthCh, value);
}
public static calculateFontSize(
endWidthCh: number,
maxFontSizePx: number,
phase: ScalingInputPhase,
value?: string,
): number {
if (_.isUndefined(value) || phase !== ScalingInputPhase.End) {
return maxFontSizePx;
}
const charactersOverMax = value.length - endWidthCh;
const scalingFactor = (1 - percentageToReduceByPerCharacter) ** charactersOverMax;
const fontSize = scalingFactor * maxFontSizePx;
return fontSize;
}
public static calculateFontSizeFromProps(props: ScalingInputProps, phase: ScalingInputPhase): number {
const { endWidthCh, value, maxFontSizePx } = props;
return ScalingInput.calculateFontSize(endWidthCh, maxFontSizePx, phase, value);
}
public getSnapshotBeforeUpdate(): ScalingInputSnapshot {
return {
inputWidthPx: this._getInputWidthInPx(),
};
}
public componentDidUpdate(
prevProps: ScalingInputProps,
prevState: ScalingInputState,
snapshot: ScalingInputSnapshot,
): void {
const prevPhase = ScalingInput.getPhaseFromProps(prevProps);
const curPhase = ScalingInput.getPhaseFromProps(this.props);
const prevFontSize = ScalingInput.calculateFontSizeFromProps(prevProps, prevPhase);
const curFontSize = ScalingInput.calculateFontSizeFromProps(this.props, curPhase);
// if we went from anything else to end, fix to the current width as it shouldn't change as we grow
if (prevPhase !== ScalingInputPhase.End && curPhase === ScalingInputPhase.End) {
this.setState({
fixedWidthInPxIfExists: snapshot.inputWidthPx,
});
}
// if we end from end to to anything else, un-fix the width
if (prevPhase === ScalingInputPhase.End && curPhase !== ScalingInputPhase.End) {
this.setState({
fixedWidthInPxIfExists: undefined,
});
}
// If font size has changed, notify.
if (prevFontSize !== curFontSize) {
this.props.onFontSizeChange(curFontSize);
}
}
public render(): React.ReactNode {
const { fontColor, onChange, placeholder, value, maxLength } = this.props;
const phase = ScalingInput.getPhaseFromProps(this.props);
return (
<Input
ref={this._inputRef as any}
fontColor={fontColor}
onChange={onChange}
value={value}
placeholder={placeholder}
fontSize={`${this._calculateFontSize(phase)}px`}
width={this._calculateWidth(phase)}
maxLength={maxLength}
/>
);
}
private readonly _calculateWidth = (phase: ScalingInputPhase): string => {
const { value, startWidthCh, endWidthCh } = this.props;
if (_.isUndefined(value)) {
return `${startWidthCh}ch`;
}
if (!_.isUndefined(this.state.fixedWidthInPxIfExists)) {
return `${this.state.fixedWidthInPxIfExists}px`;
}
switch (phase) {
case ScalingInputPhase.Start:
return `${startWidthCh}ch`;
case ScalingInputPhase.Scaling:
return `${value.length}ch`;
case ScalingInputPhase.End:
return `${endWidthCh}ch`;
default:
return `${startWidthCh}ch`;
}
};
private readonly _calculateFontSize = (phase: ScalingInputPhase): number => {
return ScalingInput.calculateFontSizeFromProps(this.props, phase);
};
private readonly _getInputWidthInPx = (): number => {
const ref = this._inputRef.current;
if (!ref) {
return 0;
}
return (ref as any).getBoundingClientRect().width;
};
}
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