Some common utilities
此腳本不應該直接安裝，它是一個供其他腳本使用的函式庫。欲使用本函式庫，請在腳本 metadata 寫上： // @require https://update.greasyfork.org/scripts/558741/1712360/Common%20Utilities.js
// ==UserScript==
// @name Common Utilities
// @description Some common utilities
// @namespace https://github.com/dzist
// @version 0.0.1
// @author Dylan Zhang
// @grant GM_info
// ==/UserScript==
const utils = {
log(...args) {
console.log(
`%c${GM_info.script.name}`,
'padding: 0 4px; background: cyan; color: #000;',
...args
)
},
ensureCondition(condition, maxAttempts = 600 /* 10s */, failureMessage) {
const raf = window.requestAnimationFrame
return new Promise((resolve, reject) => {
let attempts = 0
const detect = () => {
const result = condition()
if (result) {
resolve(result)
} else if (attempts < maxAttempts) {
attempts++
raf(detect)
} else {
reject(new Error(failureMessage))
}
}
raf(detect)
})
},
ensureElement(selector, maxAttempts = 600) {
return utils.ensureCondition(
() => document.querySelector(selector),
maxAttempts,
`Could not detect ${selector} after ${maxAttempts} attempts`
)
},
getProperty(obj, ...props) {
const stack = [obj]
let current = obj
for(let i = 0, len = props.length; i < len; i++) {
const key = props[i]
// check for undefined or null
if (current == null) {
return [, stack]
}
const isArraySearch = Array.isArray(current) && isNaN(Number(key))
if (isArraySearch) {
// if the `current` value is an array and the key is not a number,
// find the first item with the key inside it.
const foundItem = current.find(item => item && item[key])
if (foundItem) {
stack.push(foundItem)
current = foundItem[key]
} else {
return [, stack]
}
} else {
current = current[key]
if (i < len - 1 && current) {
stack.push(current)
}
}
}
return [current, stack]
}
}