Código JSFuck comentado (não terminado)

jsfuck.js

/**
 * Explicando expressões:
 *
 *   (![]+[]) -> ! tem precedência em cima do concatenador "+" então ![] vira
 *               false e por conta do + vira string e o array vazio vira string
 *               vazia, tudo isso virando a string 'false'
 *
 *   ([![]]+[][[]]) -> em [![]], ![] avalia-se como false e vira [false]. [][[]]
 *                     o array mais interno converte-se para o número 0 ao passo
 *                     que está sendo tratado como índice de um array vazio e
 *                     fazendo essta expressão virar undefined, pois no array
 *                     vazio não há a posição 0. Como nem [false] nem undefined
 *                     (tipo) são number, + simboliza uma concatenação de
 *                     strings, forçando um cast em string dos membros e, ao
 *                     transformar [false] em string, ele concatena os membros
 *                     do array com ',' e realiza a conversão para os membros
 *                     também virando a string 'false' e undefined (tipo) vira a
 *                     string 'undefined'
 *
 *   +[] -> array vazio convertido a number (pelo operador unário +, que
 *          converte o operando para número) vira 0
 *
 *   +!+[]+[+[]] -> +[] vira 0, com ! (negação), vira true, com o + (unário),
 *                  vira 1, após isso, o [+[]] vira '0' (zero string) e concatena
 *                  com o 1 e vira '10' string
 *
 *   !+[]+!+[] -> 
 */

// Declarando uma instância de um array
[]
// Capturando o método filter da instância do array por meio de seleção de membro
[
    // Retira a letra f de 'false', vindo de false ![] concatenado com string vazia ([])
    (![]+[])[+[]] +
    // Retira a letra i de 'falseundefined' vindo de ![] (false) transformado em string e concatenado
    ([![]]+[][[]])[+!+[]+[+[]]] +
    // Retira a letra l de false
    (![]+[])[!+[]+!+[]] +
    // Retira a letra t de true
    (!![]+[])[+[]] +
    // Retura a letra e de true
    (!![]+[])[!+[]+!+[]+!+[]] +
    // Retira a letra r de true
    (!![]+[])[+!+[]]
]
// Selecionando o construtor da function para poder criar a função
[
    ([][(![]+[])[+[]]+([![]]+[][[]])[+!+[]+[+[]]]+(![]+[])[!+[]+!+[]]+(!![]+[])[+[]]+(!![]+[])[!+[]+!+[]+!+[]]+(!![]+[])[+!+[]]]+[])[!+[]+!+[]+!+[]] +
    (!![]+[][(![]+[])[+[]]+([![]]+[][[]])[+!+[]+[+[]]]+(![]+[])[!+[]+!+[]]+(!![]+[])[+[]]+(!![]+[])[!+[]+!+[]+!+[]]+(!![]+[])[+!+[]]])[+!+[]+[+[]]] +
    ([][[]]+[])[+!+[]]+
    (![]+[])[!+[]+!+[]+!+[]]+
    (!![]+[])[+[]]+
    (!![]+[])[+!+[]]+([][[]]+[])[+[]]+([][(![]+[])[+[]]+([![]]+[][[]])[+!+[]+[+[]]]+(![]+[])[!+[]+!+[]]+(!![]+[])[+[]]+(!![]+[])[!+[]+!+[]+!+[]]+(!![]+[])[+!+[]]]+[])[!+[]+!+[]+!+[]]+(!![]+[])[+[]]+(!![]+[][(![]+[])[+[]]+([![]]+[][[]])[+!+[]+[+[]]]+(![]+[])[!+[]+!+[]]+(!![]+[])[+[]]+(!![]+[])[!+[]+!+[]+!+[]]+(!![]+[])[+!+[]]])[+!+[]+[+[]]]+(!![]+[])[+!+[]]
]
// Passando uma função de alert("String")
(
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)
()