| 1 | /** @flow */ |
| 2 | |
| 3 | import * as React from 'react'; |
| 4 | import {useRef} from 'react'; |
| 5 | |
| 6 | import styles from './Tooltip.css'; |
| 7 | import typeof {SyntheticMouseEvent} from 'react-dom-bindings/src/events/SyntheticEvent'; |
| 8 | |
| 9 | const initialTooltipState = {height: 0, mouseX: 0, mouseY: 0, width: 0}; |
| 10 | |
| 11 | export default function Tooltip({ |
| 12 | children, |
| 13 | className, |
| 14 | label, |
| 15 | style, |
| 16 | }: any): React.Node { |
| 17 | const containerRef = useRef(null); |
| 18 | const tooltipRef = useRef(null); |
| 19 | |
| 20 | // update the position of the tooltip based on current mouse position |
| 21 | const updateTooltipPosition = (event: SyntheticMouseEvent) => { |
| 22 | const element = tooltipRef.current; |
| 23 | if (element != null) { |
| 24 | // first find the mouse position |
| 25 | const mousePosition = getMousePosition(containerRef.current, event); |
| 26 | // use the mouse position to find the position of tooltip |
| 27 | const {left, top} = getTooltipPosition(element, mousePosition); |
| 28 | // update tooltip position |
| 29 | element.style.left = left; |
| 30 | element.style.top = top; |
| 31 | } |
| 32 | }; |
| 33 | |
| 34 | const onMouseMove = (event: SyntheticMouseEvent) => { |
| 35 | updateTooltipPosition(event); |
| 36 | }; |
| 37 | |
| 38 | const tooltipClassName = label === null ? styles.hidden : ''; |
| 39 | |
| 40 | return ( |
| 41 | <div |
| 42 | className={styles.Container} |
| 43 | onMouseMove={onMouseMove} |
| 44 | ref={containerRef}> |
| 45 | <div |
| 46 | className={`${styles.Tooltip} ${tooltipClassName} ${className || ''}`} |
| 47 | ref={tooltipRef} |
| 48 | style={style}> |
| 49 | {label} |
| 50 | </div> |
| 51 | {children} |
| 52 | </div> |
| 53 | ); |
| 54 | } |
| 55 | |
| 56 | const TOOLTIP_OFFSET = 5; |
| 57 | |
| 58 | // Method used to find the position of the tooltip based on current mouse position |
| 59 | function getTooltipPosition( |
| 60 | element: empty, |
| 61 | mousePosition: { |
| 62 | height: number, |
| 63 | mouseX: number, |
| 64 | mouseY: number, |
| 65 | width: number, |
| 66 | }, |
| 67 | ): {left: string, top: string} { |
| 68 | const {height, mouseX, mouseY, width} = mousePosition; |
| 69 | let top: number | string = 0; |
| 70 | let left: number | string = 0; |
| 71 | |
| 72 | if (mouseY + TOOLTIP_OFFSET + element.offsetHeight >= height) { |
| 73 | if (mouseY - TOOLTIP_OFFSET - element.offsetHeight > 0) { |
| 74 | top = `${mouseY - element.offsetHeight - TOOLTIP_OFFSET}px`; |
| 75 | } else { |
| 76 | top = '0px'; |
| 77 | } |
| 78 | } else { |
| 79 | top = `${mouseY + TOOLTIP_OFFSET}px`; |
| 80 | } |
| 81 | |
| 82 | if (mouseX + TOOLTIP_OFFSET + element.offsetWidth >= width) { |
| 83 | if (mouseX - TOOLTIP_OFFSET - element.offsetWidth > 0) { |
| 84 | left = `${mouseX - element.offsetWidth - TOOLTIP_OFFSET}px`; |
| 85 | } else { |
| 86 | left = '0px'; |
| 87 | } |
| 88 | } else { |
| 89 | left = `${mouseX + TOOLTIP_OFFSET * 2}px`; |
| 90 | } |
| 91 | |
| 92 | return {left, top}; |
| 93 | } |
| 94 | |
| 95 | // method used to find the current mouse position inside the container |
| 96 | function getMousePosition( |
| 97 | relativeContainer: null, |
| 98 | mouseEvent: SyntheticMouseEvent, |
| 99 | ) { |
| 100 | if (relativeContainer !== null) { |
| 101 | // Position within the nearest position:relative container. |
| 102 | let targetContainer = relativeContainer; |
| 103 | while (targetContainer.parentElement != null) { |
| 104 | // $FlowFixMe[invalid-compare] |
| 105 | if (targetContainer.style.position === 'relative') { |
| 106 | break; |
| 107 | } else { |
| 108 | targetContainer = targetContainer.parentElement; |
| 109 | } |
| 110 | } |
| 111 | |
| 112 | const {height, left, top, width} = |
| 113 | targetContainer.getBoundingClientRect() as { |
| 114 | height: number, |
| 115 | left: number, |
| 116 | top: number, |
| 117 | width: number, |
| 118 | }; |
| 119 | |
| 120 | const mouseX = mouseEvent.clientX - left; |
| 121 | const mouseY = mouseEvent.clientY - top; |
| 122 | |
| 123 | return {height, mouseX, mouseY, width}; |
| 124 | } else { |
| 125 | return initialTooltipState; |
| 126 | } |
| 127 | } |