摘要：如果類型轉(zhuǎn)換你還不是很了解，可以先讀下這篇來理解一下從看隱式強(qiáng)制轉(zhuǎn)換機(jī)制。函數(shù)可對通過編碼的字符串進(jìn)行解碼。而作者封裝的也是基于這兩者來實(shí)現(xiàn)輸出黑魔法字符串的。同時(shí)通過，返回了一個(gè)匿名函數(shù)形成了閉包。為了達(dá)到裝逼的效果。

事情的起因是這段看起來不像代碼的代碼：

有興趣的同學(xué)可以自己先嘗試下！

([]+[][(![]+[])[!+[]+!![]+!![]]+([]+{})[+!![]]+(!![]+[])[+!![]]+(!![]+[])[+[]]][([]+{})[!+[]+!![]+!![]+!![]+!![]]+([]+{})[+!![]]+([][[]]+[])[+!![]]+(![]+[])[!+[]+!![]+!![]]+(!![]+[])[+[]]+(!![]+[])[+!![]]+([][[]]+[])[+[]]+([]+{})[!+[]+!![]+!![]+!![]+!![]]+(!![]+[])[+[]]+([]+{})[+!![]]+(!![]+[])[+!![]]]((!![]+[])[+!![]]+([][[]]+[])[!+[]+!![]+!![]]+(!![]+[])[+[]]+([][[]]+[])[+[]]+(!![]+[])[+!![]]+([][[]]+[])[+!![]]+([]+{})[!+[]+!![]+!![]+!![]+!![]+!![]+!![]]+(![]+[])[!+[]+!![]]+([]+{})[+!![]]+([]+{})[!+[]+!![]+!![]+!![]+!![]]+(+{}+[])[+!![]]+(!![]+[])[+[]]+([][[]]+[])[!+[]+!![]+!![]+!![]+!![]]+([]+{})[+!![]]+([][[]]+[])[+!![]])())[+[]]+([][[]]+[])[!+[]+!![]+!![]]+(![]+[])[!+[]+!![]]+(![]+[])[!+[]+!![]]+([]+{})[+!![]]+([]+{})[!+[]+!![]+!![]+!![]+!![]+!![]+!![]]+[][(![]+[])[!+[]+!![]+!![]]+([]+{})[+!![]]+(!![]+[])[+!![]]+(!![]+[])[+[]]][([]+{})[!+[]+!![]+!![]+!![]+!![]]+([]+{})[+!![]]+([][[]]+[])[+!![]]+(![]+[])[!+[]+!![]+!![]]+(!![]+[])[+[]]+(!![]+[])[+!![]]+([][[]]+[])[+[]]+([]+{})[!+[]+!![]+!![]+!![]+!![]]+(!![]+[])[+[]]+([]+{})[+!![]]+(!![]+[])[+!![]]]((!![]+[])[+!![]]+([][[]]+[])[!+[]+!![]+!![]]+(!![]+[])[+[]]+([][[]]+[])[+[]]+(!![]+[])[+!![]]+([][[]]+[])[+!![]]+([]+{})[!+[]+!![]+!![]+!![]+!![]+!![]+!![]]+([][[]]+[])[+[]]+([][[]]+[])[+!![]]+([][[]]+[])[!+[]+!![]+!![]]+(![]+[])[!+[]+!![]+!![]]+([]+{})[!+[]+!![]+!![]+!![]+!![]]+(+{}+[])[+!![]]+([]+[][(![]+[])[!+[]+!![]+!![]]+([]+{})[+!![]]+(!![]+[])[+!![]]+(!![]+[])[+[]]][([]+{})[!+[]+!![]+!![]+!![]+!![]]+([]+{})[+!![]]+([][[]]+[])[+!![]]+(![]+[])[!+[]+!![]+!![]]+(!![]+[])[+[]]+(!![]+[])[+!![]]+([][[]]+[])[+[]]+([]+{})[!+[]+!![]+!![]+!![]+!![]]+(!![]+[])[+[]]+([]+{})[+!![]]+(!![]+[])[+!![]]]((!![]+[])[+!![]]+([][[]]+[])[!+[]+!![]+!![]]+(!![]+[])[+[]]+([][[]]+[])[+[]]+(!![]+[])[+!![]]+([][[]]+[])[+!![]]+([]+{})[!+[]+!![]+!![]+!![]+!![]+!![]+!![]]+(![]+[])[!+[]+!![]]+([]+{})[+!![]]+([]+{})[!+[]+!![]+!![]+!![]+!![]]+(+{}+[])[+!![]]+(!![]+[])[+[]]+([][[]]+[])[!+[]+!![]+!![]+!![]+!![]]+([]+{})[+!![]]+([][[]]+[])[+!![]])())[!+[]+!![]+!![]]+([][[]]+[])[!+[]+!![]+!![]])()([][(![]+[])[!+[]+!![]+!![]]+([]+{})[+!![]]+(!![]+[])[+!![]]+(!![]+[])[+[]]][([]+{})[!+[]+!![]+!![]+!![]+!![]]+([]+{})[+!![]]+([][[]]+[])[+!![]]+(![]+[])[!+[]+!![]+!![]]+(!![]+[])[+[]]+(!![]+[])[+!![]]+([][[]]+[])[+[]]+([]+{})[!+[]+!![]+!![]+!![]+!![]]+(!![]+[])[+[]]+([]+{})[+!![]]+(!![]+[])[+!![]]]((!![]+[])[+!![]]+([][[]]+[])[!+[]+!![]+!![]]+(!![]+[])[+[]]+([][[]]+[])[+[]]+(!![]+[])[+!![]]+([][[]]+[])[+!![]]+([]+{})[!+[]+!![]+!![]+!![]+!![]+!![]+!![]]+([][[]]+[])[!+[]+!![]+!![]]+(![]+[])[!+[]+!![]+!![]]+([]+{})[!+[]+!![]+!![]+!![]+!![]]+(+{}+[])[+!![]]+([]+[][(![]+[])[!+[]+!![]+!![]]+([]+{})[+!![]]+(!![]+[])[+!![]]+(!![]+[])[+[]]][([]+{})[!+[]+!![]+!![]+!![]+!![]]+([]+{})[+!![]]+([][[]]+[])[+!![]]+(![]+[])[!+[]+!![]+!![]]+(!![]+[])[+[]]+(!![]+[])[+!![]]+([][[]]+[])[+[]]+([]+{})[!+[]+!![]+!![]+!![]+!![]]+(!![]+[])[+[]]+([]+{})[+!![]]+(!![]+[])[+!![]]]((!![]+[])[+!![]]+([][[]]+[])[!+[]+!![]+!![]]+(!![]+[])[+[]]+([][[]]+[])[+[]]+(!![]+[])[+!![]]+([][[]]+[])[+!![]]+([]+{})[!+[]+!![]+!![]+!![]+!![]+!![]+!![]]+(![]+[])[!+[]+!![]]+([]+{})[+!![]]+([]+{})[!+[]+!![]+!![]+!![]+!![]]+(+{}+[])[+!![]]+(!![]+[])[+[]]+([][[]]+[])[!+[]+!![]+!![]+!![]+!![]]+([]+{})[+!![]]+([][[]]+[])[+!![]])())[!+[]+!![]+!![]]+([][[]]+[])[!+[]+!![]+!![]])()(([]+{})[+[]])[+[]]+(!+[]+!![]+!![]+!![]+!![]+!![]+!![]+[])+(!+[]+!![]+!![]+!![]+!![]+!![]+!![]+[]))+([]+{})[+!![]]+(!![]+[])[+!![]]+(![]+[])[!+[]+!![]]+([][[]]+[])[!+[]+!![]]+[][(![]+[])[!+[]+!![]+!![]]+([]+{})[+!![]]+(!![]+[])[+!![]]+(!![]+[])[+[]]][([]+{})[!+[]+!![]+!![]+!![]+!![]]+([]+{})[+!![]]+([][[]]+[])[+!![]]+(![]+[])[!+[]+!![]+!![]]+(!![]+[])[+[]]+(!![]+[])[+!![]]+([][[]]+[])[+[]]+([]+{})[!+[]+!![]+!![]+!![]+!![]]+(!![]+[])[+[]]+([]+{})[+!![]]+(!![]+[])[+!![]]]((!![]+[])[+!![]]+([][[]]+[])[!+[]+!![]+!![]]+(!![]+[])[+[]]+([][[]]+[])[+[]]+(!![]+[])[+!![]]+([][[]]+[])[+!![]]+([]+{})[!+[]+!![]+!![]+!![]+!![]+!![]+!![]]+([][[]]+[])[+[]]+([][[]]+[])[+!![]]+([][[]]+[])[!+[]+!![]+!![]]+(![]+[])[!+[]+!![]+!![]]+([]+{})[!+[]+!![]+!![]+!![]+!![]]+(+{}+[])[+!![]]+([]+[][(![]+[])[!+[]+!![]+!![]]+([]+{})[+!![]]+(!![]+[])[+!![]]+(!![]+[])[+[]]][([]+{})[!+[]+!![]+!![]+!![]+!![]]+([]+{})[+!![]]+([][[]]+[])[+!![]]+(![]+[])[!+[]+!![]+!![]]+(!![]+[])[+[]]+(!![]+[])[+!![]]+([][[]]+[])[+[]]+([]+{})[!+[]+!![]+!![]+!![]+!![]]+(!![]+[])[+[]]+([]+{})[+!![]]+(!![]+[])[+!![]]]((!![]+[])[+!![]]+([][[]]+[])[!+[]+!![]+!![]]+(!![]+[])[+[]]+([][[]]+[])[+[]]+(!![]+[])[+!![]]+([][[]]+[])[+!![]]+([]+{})[!+[]+!![]+!![]+!![]+!![]+!![]+!![]]+(![]+[])[!+[]+!![]]+([]+{})[+!![]]+([]+{})[!+[]+!![]+!![]+!![]+!![]]+(+{}+[])[+!![]]+(!![]+[])[+[]]+([][[]]+[])[!+[]+!![]+!![]+!![]+!![]]+([]+{})[+!![]]+([][[]]+[])[+!![]])())[!+[]+!![]+!![]]+([][[]]+[])[!+[]+!![]+!![]])()([][(![]+[])[!+[]+!![]+!![]]+([]+{})[+!![]]+(!![]+[])[+!![]]+(!![]+[])[+[]]][([]+{})[!+[]+!![]+!![]+!![]+!![]]+([]+{})[+!![]]+([][[]]+[])[+!![]]+(![]+[])[!+[]+!![]+!![]]+(!![]+[])[+[]]+(!![]+[])[+!![]]+([][[]]+[])[+[]]+([]+{})[!+[]+!![]+!![]+!![]+!![]]+(!![]+[])[+[]]+([]+{})[+!![]]+(!![]+[])[+!![]]]((!![]+[])[+!![]]+([][[]]+[])[!+[]+!![]+!![]]+(!![]+[])[+[]]+([][[]]+[])[+[]]+(!![]+[])[+!![]]+([][[]]+[])[+!![]]+([]+{})[!+[]+!![]+!![]+!![]+!![]+!![]+!![]]+([][[]]+[])[!+[]+!![]+!![]]+(![]+[])[!+[]+!![]+!![]]+([]+{})[!+[]+!![]+!![]+!![]+!![]]+(+{}+[])[+!![]]+([]+[][(![]+[])[!+[]+!![]+!![]]+([]+{})[+!![]]+(!![]+[])[+!![]]+(!![]+[])[+[]]][([]+{})[!+[]+!![]+!![]+!![]+!![]]+([]+{})[+!![]]+([][[]]+[])[+!![]]+(![]+[])[!+[]+!![]+!![]]+(!![]+[])[+[]]+(!![]+[])[+!![]]+([][[]]+[])[+[]]+([]+{})[!+[]+!![]+!![]+!![]+!![]]+(!![]+[])[+[]]+([]+{})[+!![]]+(!![]+[])[+!![]]]((!![]+[])[+!![]]+([][[]]+[])[!+[]+!![]+!![]]+(!![]+[])[+[]]+([][[]]+[])[+[]]+(!![]+[])[+!![]]+([][[]]+[])[+!![]]+([]+{})[!+[]+!![]+!![]+!![]+!![]+!![]+!![]]+(![]+[])[!+[]+!![]]+([]+{})[+!![]]+([]+{})[!+[]+!![]+!![]+!![]+!![]]+(+{}+[])[+!![]]+(!![]+[])[+[]]+([][[]]+[])[!+[]+!![]+!![]+!![]+!![]]+([]+{})[+!![]]+([][[]]+[])[+!![]])())[!+[]+!![]+!![]]+([][[]]+[])[!+[]+!![]+!![]])()(([]+{})[+[]])[+[]]+(!+[]+!![]+[])+(+!![]+[]))

作者對著這段代碼足足看了一下午，我只想說這不是什么深?yuàn)W的黑魔法。一點(diǎn)點(diǎn)看下來你就知道其中的原理了。最后會(huì)有一段作者自己封裝的代碼叫nb.js（源碼在這里），它實(shí)現(xiàn)了輸入數(shù)字字母后自動(dòng)生成這種玄學(xué)代碼片段。就像這樣：

歡迎關(guān)注我的博客，不定期更新中——

——何時(shí)完結(jié)不確定，寫多少看我會(huì)多少！這是已經(jīng)更新的地址：

小眾系列之按位非運(yùn)算符：JavaScript中奇特的~運(yùn)算符

小眾系列之終極類型轉(zhuǎn)換：從hello world看JavaScript隱藏的黑魔法制

小眾系列之隱式類型轉(zhuǎn)換：[從[] == ![]看隱式強(qiáng)制轉(zhuǎn)換機(jī)制](https://github.com/Aaaaaaaty/...

小眾系列之事件循環(huán)：從HTML5與PromiseA+規(guī)范來看事件循環(huán)

這個(gè)系列旨在對一些人們不常用遇到的知識(shí)點(diǎn)，以及可能常用到但不曾深入了解的部分做一個(gè)重新梳理，雖然可能有些部分看起來沒有什么用，因?yàn)槠綍r(shí)開發(fā)真的用不到！但個(gè)人認(rèn)為糟粕也好精華也罷里面全部蘊(yùn)藏著JS一些偏本質(zhì)的東西或者說底層規(guī)范，如果能適當(dāng)避開舒適區(qū)來看這些小細(xì)節(jié)，也許對自己也會(huì)有些幫助~文章更新在我的博客，歡迎不定期關(guān)注。

什么意思？比如：f。看到f你會(huì)想到哪個(gè)關(guān)鍵字？同時(shí)這個(gè)關(guān)鍵字是要在類型轉(zhuǎn)換的機(jī)制下能夠被打印出來的。如果類型轉(zhuǎn)換你還不是很了解，可以先讀下這篇來理解一下：[從[] == ![]看隱式強(qiáng)制轉(zhuǎn)換機(jī)制](https://github.com/Aaaaaaaty/...。我相信很多同學(xué)可以想到是false這個(gè)關(guān)鍵字。那么我們的思路就有了也就是要讓代碼實(shí)現(xiàn)"false"[0]這件事，這個(gè)認(rèn)識(shí)統(tǒng)一之后我相信下面的代碼一定不難理解了：

[[[] == []] + []][+![]][+![]]
//過程理解為
[] == [] => false
[[] == []] => [false]
[[[] == []] + []] => ["false"], [+![]] => 0
[[[] == []] + []][+![]] => "false"
[[[] == []] + []][+![]][+![]] => "false"[0] => "f"

其中大體形式可以理解為："false"[0] => "f"

是不是瞬間覺得也不過如此？

當(dāng)你知道可以用上面的方式來獲取自己需要的字母之后，接下來要做的是思考一下你能從關(guān)鍵字中獲取哪些字母呢，作者總結(jié)了以下你可以通過關(guān)鍵字獲得的字母：

([][[]]+[]) => "undefined"
+[1+[[][0]+[]][0][3]+400][0]+[] => "Infinity"
[[[] == []] + []][+![]] => "false"
[[[] != []] + []][+![]] => "true"
([]+{}) => "[object Object]"

感興趣的同學(xué)自己打印下就明白為什么了。

接下來要說的是剩下的字母怎么辦？當(dāng)然了你仍然可以通過試圖尋找關(guān)鍵字的方式來獲取字母。但是如果標(biāo)點(diǎn)我也想要呢？或者說26個(gè)字母我都想要怎么辦？
具體點(diǎn)來說對于“hello world！”這段字符串來看，至少“w”,"!"的獲取方法通過關(guān)鍵字的形式我們是無從下手的。

unescape() 函數(shù)可對通過 escape() 編碼的字符串進(jìn)行解碼。但是已經(jīng)廢棄了

是的現(xiàn)在已經(jīng)不建議如此使用了，但是瀏覽器下基本還是支持這個(gè)函數(shù)的。通過這個(gè)函數(shù)我們可以通過ascll碼來直接得到我們需要的字符：

unescape("%77") => "w"

如此看來，除了我們可以快速得得到一些關(guān)鍵字字母外，用這個(gè)方法我們便可以實(shí)現(xiàn)任意字母的組合。而作者封裝的nb.js也是基于這兩者來實(shí)現(xiàn)輸出黑魔法字符串的。

那么現(xiàn)在的問題是如果通過字符串來執(zhí)行unescape("%77")這段代碼？

在這里也不繞彎子了，作者打印了很多次之后才發(fā)現(xiàn)是如此調(diào)用的：

[]["sort"]["constructor"]("return unescape")

因?yàn)镴S調(diào)用方法不光是“.”調(diào)用，通過[]也是可以調(diào)用的。同時(shí)通過return unescape，返回了一個(gè)匿名函數(shù)形成了閉包。故調(diào)用的時(shí)候采用如下方式：

[]["sort"]["constructor"]("return unescape")()("%77") => "w"

至于為什么這段代碼寫出來如此長是因?yàn)樯厦娴拿恳粋€(gè)字母都是一點(diǎn)點(diǎn)拼出來的，也行好上面通過關(guān)鍵字的方式可以得到這些字母=。=不然的話——

所以經(jīng)過上面的分析你會(huì)發(fā)現(xiàn)，除了字符串長度感人之外，這種通過拼接字符串可以返回函數(shù)并且執(zhí)行的方式還真是蠻炫酷的。為了達(dá)到裝逼的效果。作者決定封裝一個(gè)支持字母和數(shù)字的函數(shù)，當(dāng)你傳入普通的字符串之后，會(huì)返回帶有黑魔法氣息的冗長字符串，盡情拿去裝x吧，不客氣~

var baseAlibrary = {
    "a": "[[[] == []][0]+[]][0][1]",
    "b": null,
    "c": "[[][[[][0] + []][0][4]+[[][0] + []][0][5]+[[][0] + []][0][1]+[[][0] + []][0][2]]+[]][0][3]",
    "d": "([][[]]+[])[+!![]+!![]]",
    "e": "([][[]]+[])[+!![]+!![]+!![]]",
    "f": "([][[]]+[])[+!![]+!![]+!![]+!![]]",
    "g": null,
    ...
    "0": "(+![])",
    "1": "(+!![])",
    "2": "(+!![]+!![])",
    ...
    ",": null,
    "!": null,
    }
    var ascll = { //ascll表可自行配置, 新添加后需要在上面對象中配置相同key，只是value為null
        "A": "41",
        "B": "42",
        ...
    }

將簡單的字母轉(zhuǎn)換方式直接存儲(chǔ)下來，如果需要的字符無法從基礎(chǔ)對象獲取，就記為null，并在ascll表中寫入相關(guān)轉(zhuǎn)碼方式。

var result = ""
    var unescapeStr = "[][(![]+[])[!+[]+!![]+!![]]+([]+{})[+!![]]+(!![]+[])[+!![]]+(!![]+[])[+[]]][([]+{})[!+[]+!![]+!![]+!![]+!![]]+([]+{})[+!![]]+([][[]]+[])[+!![]]+(![]+[])[!+[]+!![]+!![]]+(!![]+[])[+[]]+(!![]+[])[+!![]]+([][[]]+[])[+[]]+([]+{})[!+[]+!![]+!![]+!![]+!![]]+(!![]+[])[+[]]+([]+{})[+!![]]+(!![]+[])[+!![]]]((!![]+[])[+!![]]+([][[]]+[])[!+[]+!![]+!![]]+(!![]+[])[+[]]+([][[]]+[])[+[]]+(!![]+[])[+!![]]+([][[]]+[])[+!![]]+([]+{})[!+[]+!![]+!![]+!![]+!![]+!![]+!![]]+([][[]]+[])[+[]]+([][[]]+[])[+!![]]+([][[]]+[])[!+[]+!![]+!![]]+(![]+[])[!+[]+!![]+!![]]+([]+{})[!+[]+!![]+!![]+!![]+!![]]+(+{}+[])[+!![]]+([]+[][(![]+[])[!+[]+!![]+!![]]+([]+{})[+!![]]+(!![]+[])[+!![]]+(!![]+[])[+[]]][([]+{})[!+[]+!![]+!![]+!![]+!![]]+([]+{})[+!![]]+([][[]]+[])[+!![]]+(![]+[])[!+[]+!![]+!![]]+(!![]+[])[+[]]+(!![]+[])[+!![]]+([][[]]+[])[+[]]+([]+{})[!+[]+!![]+!![]+!![]+!![]]+(!![]+[])[+[]]+([]+{})[+!![]]+(!![]+[])[+!![]]]((!![]+[])[+!![]]+([][[]]+[])[!+[]+!![]+!![]]+(!![]+[])[+[]]+([][[]]+[])[+[]]+(!![]+[])[+!![]]+([][[]]+[])[+!![]]+([]+{})[!+[]+!![]+!![]+!![]+!![]+!![]+!![]]+(![]+[])[!+[]+!![]]+([]+{})[+!![]]+([]+{})[!+[]+!![]+!![]+!![]+!![]]+(+{}+[])[+!![]]+(!![]+[])[+[]]+([][[]]+[])[!+[]+!![]+!![]+!![]+!![]]+([]+{})[+!![]]+([][[]]+[])[+!![]])())[!+[]+!![]+!![]]+([][[]]+[])[!+[]+!![]+!![]])"
    //將[]["sort"]["constructor"]("return unescape")的黑魔法形式存儲(chǔ)起來之后直接調(diào)用
    function changeAscll(ascllItem) {
        var ascllResult = ""
        var middleValue = ""
        ascll[ascllItem].split("").forEach(function(item) {
            if(isNaN(item)) { //ascll中遇到字母則需要再次進(jìn)行unescape轉(zhuǎn)碼
                var str = ""
                ascll[item].split("").forEach(function(data) {
                    str += "+[" + baseAlibrary[data] + "]"
                })
                middleValue += "+" + unescapeStr + "()("+ baseAlibrary["%"]+"+" +  str.slice(1) + ")"
            } else {
                middleValue += "+[" + baseAlibrary[item] + "]"
            }    
        })
        ascllResult += "+" + unescapeStr + "()("+ baseAlibrary["%"]+"+" +  middleValue.slice(1) + ")"
        return ascllResult
    }
    function getUnEscape(str) {

    }
    strArr.forEach(function(item) {
        Object.keys(baseAlibrary).forEach(function(obj, i) {
            if(item.toLocaleLowerCase() === obj) {
                if(!baseAlibrary[item]) {
                    Object.keys(ascll).forEach(function(ascllItem) {
                        if(obj === ascllItem) {
                            var cbValue = changeAscll(ascllItem).slice(1)
                            result += "+" + cbValue
                        }
                    })
                } else {
                    result += "+" + baseAlibrary[obj]
                }
            }
        })
    })
    console.log(result.slice(1))

也就是一開始大家看到的：

作者將函數(shù)綁定在了this上，通過this.reallyNb()即可得到你想要的~

PS：代碼請部署在服務(wù)器中再打開頁面，否則個(gè)別字母通過location方法會(huì)取不到，主要就是t,p。不過這個(gè)問題之后作者會(huì)將其以ascll表的方式存儲(chǔ)，就沒有環(huán)境限制了。只是作者嫌棄那樣做打印的字符串太長了~

不定時(shí)更新中——
有問題歡迎在issues下交流。