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const placeHolderElemAttr = {
    position: 'absolute',
    top: '-99999px',
    left: '-99999px',
    width: '100px',
    height: '100px',
    overflow: 'scroll'
};

interface CalcScrollbarSize {

liuwenzhuang

module.exports = function ({ types: t }) {
    let hasUserTokenImport = false;
    let defaultImportIdentifier = '';
    return {
        visitor: {
            Program: {
                enter(path) {
                    const children = path.node.body;
                    const userTokenImportIndex = children.findIndex(item => {
                        if (item.type !== 'ImportDeclaration') {

liuwenzhuang

class GraphNode {
  public neighbors: Set<GraphNode>
  public color: string
  constructor(public label) {
    this.label = label;
    this.neighbors = new Set();
    this.color = null;
  }
}

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function mergeArrays(leftArray, rightArray) {
  const result = [];
  
  let leftIndex = 0;
  let rightIndex = 0;
  const leftLen = leftArray.length;
  const rightLen = rightArray.length;
  
  while(result.length < leftLen + rightLen) {
    if (leftIndex < leftLen && (rightIndex === rightLen || leftArray[leftIndex] < rightArray[rightIndex])) {

liuwenzhuang

class DumpMap {
    hashTable: Array<Array<[string, any]>>
    constructor() {
        this.hashTable = []
    }

    get(x: string) {
        const index = hash(x)
        const backets = this.hashTable[index]
        if (!backets) {

liuwenzhuang

import { fromEvent, of, EMPTY } from 'rxjs';
import { switchMap } from 'rxjs/operators';
import { isEmpty } from 'lodash';

function bindKeyboardShortcuts(eventName: string, keybinding: string) {
    const keys = keybinding.split('.').map(key => key.toLowerCase());
    const allModifierKeys = ['ctrl', 'shift', 'alt', 'cmd', 'meta']; // meta === cmd
    const modifierKeys = keys.filter(key => allModifierKeys.indexOf(key) !== -1);
    return fromEvent(document, eventName).pipe(
        switchMap((e: KeyboardEvent) => {

liuwenzhuang

import { iif, of, Subject } from 'rxjs';
import { switchMap, delay, finalize } from 'rxjs/operators';
import { ajax } from 'rxjs/ajax';

const loadingSubject = new Subject<boolean>();

const loading$ = loadingSubject.pipe(
  switchMap(flag => {
    return iif(
      () => flag,

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/**
 * console order is:
 * main call stack start
 * main callback stack end
 * Promise
 * mutate
 * setTimeout
 *
 * @see https://jakearchibald.com/2015/tasks-microtasks-queues-and-schedules/
 * callback of Promise, MutationObserver(as microtasks) has higher privilege then setTimeout callback

liuwenzhuang

const worker = new Worker('worker.js')

// handle data from worker
worker.addEventListener('message', (e) => {
  console.log('worker send data back:', e.data)
}, false);

// handle error
worker.addEventListener('error', (err) => {
  console.log(`Error: Line ${err.lineno} in ${err.filename} : ${e.message}`);

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class Graph {
  public adjList = new Map<any, any[]>();
  public numberOfVertexs: number = 0;

  public addVertex(vertex) {
    this.adjList.set(vertex, []);
    this.numberOfVertexs ++;
  }

  public addEdge(vertex1, vertex2) {