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MiddleTruncate component
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| export const measureText = (container: HTMLElement) => { | |
| const span = document.createElement('span'); | |
| span.style.opacity = '0'; | |
| span.style.position = 'absolute'; | |
| span.style.top = '-1000px'; | |
| span.style.left = '-1000px'; | |
| span.style.whiteSpace = 'nowrap'; | |
| span.style.pointerEvents = 'none'; | |
| container.appendChild(span); | |
| return { | |
| measure: (text: string) => { | |
| span.innerText = text; | |
| return span.clientWidth; | |
| }, | |
| destroy: () => { | |
| container.removeChild(span); | |
| }, | |
| }; | |
| }; | |
| export const getMiddleTruncatedString = ( | |
| text: string, | |
| ellipsis: string, | |
| container: HTMLElement | |
| ): string => { | |
| if (!text) return text; | |
| const { measure: getTextWidth, destroy: destroyMeasure } = | |
| measureText(container); | |
| const textWidth = getTextWidth(text); | |
| const containerWidth = container.clientWidth; | |
| const initialOffset = Math.floor((containerWidth / textWidth) * text.length); | |
| if (textWidth <= containerWidth) { | |
| destroyMeasure(); | |
| return text; | |
| } | |
| let offset = initialOffset; | |
| const attempts: Record<number, [number, string]> = {}; | |
| const maxAttempts = 20; | |
| const buffer = 10; | |
| while (Object.values(attempts).length <= maxAttempts) { | |
| // If we have already tried this offset, stop | |
| if (attempts[offset]) break; | |
| // If we are at the beginning of the string, just return the ellipsis | |
| if (offset <= 1) { | |
| attempts[0] = [0, ellipsis]; | |
| break; | |
| } | |
| const start = text | |
| .slice(0, Math.ceil((offset - ellipsis.length) / 2 - 1)) | |
| .trimEnd(); | |
| const end = text | |
| .slice(Math.floor((offset - ellipsis.length) / 2) - offset) | |
| .trimStart(); | |
| const truncatedStr = start + ellipsis + end; | |
| const width = getTextWidth(truncatedStr); | |
| attempts[offset] = [width, truncatedStr]; | |
| if (width >= containerWidth) { | |
| offset = offset - 2; | |
| } else { | |
| // If we are close to the container width, stop | |
| if (containerWidth - width < buffer) break; | |
| offset = offset + 2; | |
| } | |
| } | |
| // Remove the span element used for measuring text | |
| destroyMeasure(); | |
| // Find the closest attempt that is smaller than the container width | |
| return ( | |
| Object.values(attempts) | |
| .reverse() | |
| .find(([width]) => width < containerWidth)?.[1] ?? | |
| Object.values(attempts)[0][1] | |
| ); | |
| }; |
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| import React, { useRef, useLayoutEffect, useState } from 'react'; | |
| //Chakra Hint component | |
| import Hint from '../Hint'; | |
| import { getMiddleTruncatedString } from './helpers'; | |
| export type Props = { | |
| text: string; | |
| } & React.CSSProperties; | |
| export default function MiddleTruncate({ text, ...style }: Props) { | |
| const containerRef = useRef<HTMLDivElement | null>(null); | |
| const [truncatedString, setTruncatedString] = useState(text); | |
| useLayoutEffect(() => { | |
| let cancellationToken = { cancelled: false }; | |
| const container = containerRef.current; | |
| if (!container) return; | |
| const calculateTruncatedString = () => { | |
| if (cancellationToken) cancellationToken.cancelled = true; | |
| const requestCancellationToken = { cancelled: false }; | |
| cancellationToken = requestCancellationToken; | |
| const truncated = getMiddleTruncatedString(text, '\u2026', container); | |
| if (requestCancellationToken.cancelled) return; | |
| setTruncatedString(truncated); | |
| }; | |
| window.document.fonts?.ready?.then(calculateTruncatedString); | |
| const observer = new ResizeObserver(() => { | |
| window.requestAnimationFrame(calculateTruncatedString); | |
| }); | |
| observer.observe(container); | |
| return () => { | |
| cancellationToken.cancelled = true; | |
| observer.disconnect(); | |
| }; | |
| }, [text]); | |
| return ( | |
| <div | |
| data-testid="middle-truncate-container" | |
| ref={containerRef} | |
| style={{ | |
| overflow: 'hidden', | |
| textOverflow: 'clip', | |
| whiteSpace: 'nowrap', | |
| flexGrow: 1, | |
| ...style, | |
| }} | |
| > | |
| {text === truncatedString ? ( | |
| text | |
| ) : ( | |
| <Hint label={text}>{truncatedString}</Hint> | |
| )} | |
| </div> | |
| ); | |
| } |
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Hi, one problem when I'm using your code is that resizeObserver is triggered when measuring the text 🥲 so that the truncated text ends up being "..." only 😭
Update: I see, the container has to have display: block style 😂