excalidraw/src/utils.ts

import colors from "./colors";
import {
  CURSOR_TYPE,
  DEFAULT_VERSION,
  FONT_FAMILY,
  WINDOWS_EMOJI_FALLBACK_FONT,
} from "./constants";
import { FontFamilyValues, FontString } from "./element/types";
import { Zoom } from "./types";
import { unstable_batchedUpdates } from "react-dom";
import { isDarwin } from "./keys";

let mockDateTime: string | null = null;

export const setDateTimeForTests = (dateTime: string) => {
  mockDateTime = dateTime;
};

export const getDateTime = () => {
  if (mockDateTime) {
    return mockDateTime;
  }

  const date = new Date();
  const year = date.getFullYear();
  const month = `${date.getMonth() + 1}`.padStart(2, "0");
  const day = `${date.getDate()}`.padStart(2, "0");
  const hr = `${date.getHours()}`.padStart(2, "0");
  const min = `${date.getMinutes()}`.padStart(2, "0");

  return `${year}-${month}-${day}-${hr}${min}`;
};

export const capitalizeString = (str: string) =>
  str.charAt(0).toUpperCase() + str.slice(1);

export const isToolIcon = (
  target: Element | EventTarget | null,
): target is HTMLElement =>
  target instanceof HTMLElement && target.className.includes("ToolIcon");

export const isInputLike = (
  target: Element | EventTarget | null,
): target is
  | HTMLInputElement
  | HTMLTextAreaElement
  | HTMLSelectElement
  | HTMLBRElement
  | HTMLDivElement =>
  (target instanceof HTMLElement && target.dataset.type === "wysiwyg") ||
  target instanceof HTMLBRElement || // newline in wysiwyg
  target instanceof HTMLInputElement ||
  target instanceof HTMLTextAreaElement ||
  target instanceof HTMLSelectElement;

export const isWritableElement = (
  target: Element | EventTarget | null,
): target is
  | HTMLInputElement
  | HTMLTextAreaElement
  | HTMLBRElement
  | HTMLDivElement =>
  (target instanceof HTMLElement && target.dataset.type === "wysiwyg") ||
  target instanceof HTMLBRElement || // newline in wysiwyg
  target instanceof HTMLTextAreaElement ||
  (target instanceof HTMLInputElement &&
    (target.type === "text" || target.type === "number"));

export const getFontFamilyString = ({
  fontFamily,
}: {
  fontFamily: FontFamilyValues;
}) => {
  for (const [fontFamilyString, id] of Object.entries(FONT_FAMILY)) {
    if (id === fontFamily) {
      return `${fontFamilyString}, ${WINDOWS_EMOJI_FALLBACK_FONT}`;
    }
  }
  return WINDOWS_EMOJI_FALLBACK_FONT;
};

/** returns fontSize+fontFamily string for assignment to DOM elements */
export const getFontString = ({
  fontSize,
  fontFamily,
}: {
  fontSize: number;
  fontFamily: FontFamilyValues;
}) => {
  return `${fontSize}px ${getFontFamilyString({ fontFamily })}` as FontString;
};

// https://github.com/grassator/canvas-text-editor/blob/master/lib/FontMetrics.js
export const measureText = (text: string, font: FontString) => {
  const line = document.createElement("div");
  const body = document.body;
  line.style.position = "absolute";
  line.style.whiteSpace = "pre";
  line.style.font = font;
  body.appendChild(line);
  line.innerText = text
    .split("\n")
    // replace empty lines with single space because leading/trailing empty
    // lines would be stripped from computation
    .map((x) => x || " ")
    .join("\n");
  const width = line.offsetWidth;
  const height = line.offsetHeight;
  // Now creating 1px sized item that will be aligned to baseline
  // to calculate baseline shift
  const span = document.createElement("span");
  span.style.display = "inline-block";
  span.style.overflow = "hidden";
  span.style.width = "1px";
  span.style.height = "1px";
  line.appendChild(span);
  // Baseline is important for positioning text on canvas
  const baseline = span.offsetTop + span.offsetHeight;
  document.body.removeChild(line);

  return { width, height, baseline };
};

export const debounce = <T extends any[]>(
  fn: (...args: T) => void,
  timeout: number,
) => {
  let handle = 0;
  let lastArgs: T | null = null;
  const ret = (...args: T) => {
    lastArgs = args;
    clearTimeout(handle);
    handle = window.setTimeout(() => {
      lastArgs = null;
      fn(...args);
    }, timeout);
  };
  ret.flush = () => {
    clearTimeout(handle);
    if (lastArgs) {
      const _lastArgs = lastArgs;
      lastArgs = null;
      fn(..._lastArgs);
    }
  };
  ret.cancel = () => {
    lastArgs = null;
    clearTimeout(handle);
  };
  return ret;
};

export const selectNode = (node: Element) => {
  const selection = window.getSelection();
  if (selection) {
    const range = document.createRange();
    range.selectNodeContents(node);
    selection.removeAllRanges();
    selection.addRange(range);
  }
};

export const removeSelection = () => {
  const selection = window.getSelection();
  if (selection) {
    selection.removeAllRanges();
  }
};

export const distance = (x: number, y: number) => Math.abs(x - y);

export const resetCursor = (canvas: HTMLCanvasElement | null) => {
  if (canvas) {
    canvas.style.cursor = "";
  }
};

export const setCursor = (canvas: HTMLCanvasElement | null, cursor: string) => {
  if (canvas) {
    canvas.style.cursor = cursor;
  }
};

export const setCursorForShape = (
  canvas: HTMLCanvasElement | null,
  shape: string,
) => {
  if (!canvas) {
    return;
  }
  if (shape === "selection") {
    resetCursor(canvas);
    // do nothing if image tool is selected which suggests there's
    // a image-preview set as the cursor
  } else if (shape !== "image") {
    canvas.style.cursor = CURSOR_TYPE.CROSSHAIR;
  }
};

export const isFullScreen = () =>
  document.fullscreenElement?.nodeName === "HTML";

export const allowFullScreen = () =>
  document.documentElement.requestFullscreen();

export const exitFullScreen = () => document.exitFullscreen();

export const getShortcutKey = (shortcut: string): string => {
  shortcut = shortcut
    .replace(/\bAlt\b/i, "Alt")
    .replace(/\bShift\b/i, "Shift")
    .replace(/\b(Enter|Return)\b/i, "Enter")
    .replace(/\bDel\b/i, "Delete");

  if (isDarwin) {
    return shortcut
      .replace(/\bCtrlOrCmd\b/i, "Cmd")
      .replace(/\bAlt\b/i, "Option");
  }
  return shortcut.replace(/\bCtrlOrCmd\b/i, "Ctrl");
};

export const viewportCoordsToSceneCoords = (
  { clientX, clientY }: { clientX: number; clientY: number },
  {
    zoom,
    offsetLeft,
    offsetTop,
    scrollX,
    scrollY,
  }: {
    zoom: Zoom;
    offsetLeft: number;
    offsetTop: number;
    scrollX: number;
    scrollY: number;
  },
) => {
  const invScale = 1 / zoom.value;
  const x = (clientX - zoom.translation.x - offsetLeft) * invScale - scrollX;
  const y = (clientY - zoom.translation.y - offsetTop) * invScale - scrollY;
  return { x, y };
};

export const sceneCoordsToViewportCoords = (
  { sceneX, sceneY }: { sceneX: number; sceneY: number },
  {
    zoom,
    offsetLeft,
    offsetTop,
    scrollX,
    scrollY,
  }: {
    zoom: Zoom;
    offsetLeft: number;
    offsetTop: number;
    scrollX: number;
    scrollY: number;
  },
) => {
  const x = (sceneX + scrollX + offsetLeft) * zoom.value + zoom.translation.x;
  const y = (sceneY + scrollY + offsetTop) * zoom.value + zoom.translation.y;
  return { x, y };
};

export const getGlobalCSSVariable = (name: string) =>
  getComputedStyle(document.documentElement).getPropertyValue(`--${name}`);

const RS_LTR_CHARS =
  "A-Za-z\u00C0-\u00D6\u00D8-\u00F6\u00F8-\u02B8\u0300-\u0590\u0800-\u1FFF" +
  "\u2C00-\uFB1C\uFDFE-\uFE6F\uFEFD-\uFFFF";
const RS_RTL_CHARS = "\u0591-\u07FF\uFB1D-\uFDFD\uFE70-\uFEFC";
const RE_RTL_CHECK = new RegExp(`^[^${RS_LTR_CHARS}]*[${RS_RTL_CHARS}]`);
/**
 * Checks whether first directional character is RTL. Meaning whether it starts
 *  with RTL characters, or indeterminate (numbers etc.) characters followed by
 *  RTL.
 * See https://github.com/excalidraw/excalidraw/pull/1722#discussion_r436340171
 */
export const isRTL = (text: string) => RE_RTL_CHECK.test(text);

export const tupleToCoors = (
  xyTuple: readonly [number, number],
): { x: number; y: number } => {
  const [x, y] = xyTuple;
  return { x, y };
};

/** use as a rejectionHandler to mute filesystem Abort errors */
export const muteFSAbortError = (error?: Error) => {
  if (error?.name === "AbortError") {
    return;
  }
  throw error;
};

export const findIndex = <T>(
  array: readonly T[],
  cb: (element: T, index: number, array: readonly T[]) => boolean,
  fromIndex: number = 0,
) => {
  if (fromIndex < 0) {
    fromIndex = array.length + fromIndex;
  }
  fromIndex = Math.min(array.length, Math.max(fromIndex, 0));
  let index = fromIndex - 1;
  while (++index < array.length) {
    if (cb(array[index], index, array)) {
      return index;
    }
  }
  return -1;
};

export const findLastIndex = <T>(
  array: readonly T[],
  cb: (element: T, index: number, array: readonly T[]) => boolean,
  fromIndex: number = array.length - 1,
) => {
  if (fromIndex < 0) {
    fromIndex = array.length + fromIndex;
  }
  fromIndex = Math.min(array.length - 1, Math.max(fromIndex, 0));
  let index = fromIndex + 1;
  while (--index > -1) {
    if (cb(array[index], index, array)) {
      return index;
    }
  }
  return -1;
};

export const isTransparent = (color: string) => {
  const isRGBTransparent = color.length === 5 && color.substr(4, 1) === "0";
  const isRRGGBBTransparent = color.length === 9 && color.substr(7, 2) === "00";
  return (
    isRGBTransparent ||
    isRRGGBBTransparent ||
    color === colors.elementBackground[0]
  );
};

export type ResolvablePromise<T> = Promise<T> & {
  resolve: [T] extends [undefined] ? (value?: T) => void : (value: T) => void;
  reject: (error: Error) => void;
};
export const resolvablePromise = <T>() => {
  let resolve!: any;
  let reject!: any;
  const promise = new Promise((_resolve, _reject) => {
    resolve = _resolve;
    reject = _reject;
  });
  (promise as any).resolve = resolve;
  (promise as any).reject = reject;
  return promise as ResolvablePromise<T>;
};

/**
 * @param func handler taking at most single parameter (event).
 */
export const withBatchedUpdates = <
  TFunction extends ((event: any) => void) | (() => void),
>(
  func: Parameters<TFunction>["length"] extends 0 | 1 ? TFunction : never,
) =>
  ((event) => {
    unstable_batchedUpdates(func as TFunction, event);
  }) as TFunction;

//https://stackoverflow.com/a/9462382/8418
export const nFormatter = (num: number, digits: number): string => {
  const si = [
    { value: 1, symbol: "b" },
    { value: 1e3, symbol: "k" },
    { value: 1e6, symbol: "M" },
    { value: 1e9, symbol: "G" },
  ];
  const rx = /\.0+$|(\.[0-9]*[1-9])0+$/;
  let index;
  for (index = si.length - 1; index > 0; index--) {
    if (num >= si[index].value) {
      break;
    }
  }
  return (
    (num / si[index].value).toFixed(digits).replace(rx, "$1") + si[index].symbol
  );
};

export const getVersion = () => {
  return (
    document.querySelector<HTMLMetaElement>('meta[name="version"]')?.content ||
    DEFAULT_VERSION
  );
};

// Adapted from https://github.com/Modernizr/Modernizr/blob/master/feature-detects/emoji.js
export const supportsEmoji = () => {
  const canvas = document.createElement("canvas");
  const ctx = canvas.getContext("2d");
  if (!ctx) {
    return false;
  }
  const offset = 12;
  ctx.fillStyle = "#f00";
  ctx.textBaseline = "top";
  ctx.font = "32px Arial";
  // Modernizr used 🐨, but it is sort of supported on Windows 7.
  // Luckily 😀 isn't supported.
  ctx.fillText("😀", 0, 0);
  return ctx.getImageData(offset, offset, 1, 1).data[0] !== 0;
};

export const getNearestScrollableContainer = (
  element: HTMLElement,
): HTMLElement | Document => {
  let parent = element.parentElement;
  while (parent) {
    if (parent === document.body) {
      return document;
    }
    const { overflowY } = window.getComputedStyle(parent);
    const hasScrollableContent = parent.scrollHeight > parent.clientHeight;
    if (
      hasScrollableContent &&
      (overflowY === "auto" || overflowY === "scroll")
    ) {
      return parent;
    }
    parent = parent.parentElement;
  }
  return document;
};

export const focusNearestParent = (element: HTMLInputElement) => {
  let parent = element.parentElement;
  while (parent) {
    if (parent.tabIndex > -1) {
      parent.focus();
      return;
    }
    parent = parent.parentElement;
  }
};

export const preventUnload = (event: BeforeUnloadEvent) => {
  event.preventDefault();
  // NOTE: modern browsers no longer allow showing a custom message here
  event.returnValue = "";
};