Shuumatsu

export const eventName = 'in view'
export const tagName = 'inview-observer'

const io = new IntersectionObserver((entries, observer) => {
    entries.forEach(entry => {
        const target = entry.target
        target.dispatchEvent(new Event('in view'))
    })
}, { threshold: 0.25 })

Shuumatsu

const gFoo = function* () {
    const a = yield Promise.resolve(1)
    const b = yield Promise.resolve(2)
    const c = yield Promise.resolve(3)
    const d = yield Promise.resolve(4)

    return [a, b, c, d]
}

const co = genF => (...args) => {

Shuumatsu

const seenKeys = new Set()
const MULTIPLIER = Math.pow(2, 24)

const generateRandomKey = () => {
    const key = Math.floor(Math.random() * MULTIPLIER).toString(32)
    if (seenKeys.has(key) || !isNaN(+key))
        return generateRandomKey()

    seenKeys.add(key)
    return key

Shuumatsu

// 常规的递归方法
const flatten1 = arr => {
    const result = []
    for (const v of arr) {
        Array.isArray(v) ?
            result.push(...flatten(v)) :
            result.push(v)
    }

    return result

Shuumatsu

const cache = new WeakMap()

export default async fileblob => new Promise((resolve, reject) => {
    if (cache.has(fileblob))
        resolve(cache.get(fileblob))

    const reader = new FileReader()
    reader.addEventListener('load', e => {
        const src = e.target.result
        cache.set(fileblob, src)

Shuumatsu

const cache = new WeakMap()

export default src => new Promise((resolve, reject) => {
    if (cache.has(src))
        resolve(cache.get(src))

    const audio = document.createElement('audio')
    audio.addEventListener('loadedmetadata', e => {
        const duration = audio.duration
        cache.set(src, duration)

Shuumatsu

http://www.ics.uci.edu/~eppstein/161/960109.html

Shuumatsu

const cache = new Map()

export default src =>
    new Promise((resolve, reject) => {
        if (cache.has(src)) resolve(cache.get(src))

        const audio = document.createElement('audio')

        audio.addEventListener('loadedmetadata', () => {
            const duration = audio.duration

Shuumatsu

export const sync = syncFn => (data, cb) => data |> syncFn |> cb;

export const compose = (taskList, cb) =>
  reduceRight((next, task) => data => task(data, next), cb, taskList);

export const withErrorHandler = handler =>
  map(task => (data, next) =>
    data instanceof Error ? handler(data) : task(data, next)
  );

Shuumatsu

import React from 'react'
import styled, { keyframes } from 'styled-components'

const Svg = styled.svg.attrs({
    version: '1.1',
    xmlns: 'http://www.w3.org/2000/svg',
    xmlnsXlink: 'http://www.w3.org/1999/xlink',
    'xmlns:sketch': 'http://www.bohemiancoding.com/sketch/ns'
})`
    position: relative;