x=''+self 

j=''

'd1d7a1712345691a7512d427b1da7d9ab7519a4b721a961721d694'

.split``

.map(_=>j+=`x[0x${_}]+`)

console.log(eval(j+'""'))

x=''+self 

// becomes "[object Window]"

j='' 

// initialize `j` which will be javascript to pass to `eval`

'd1d7a17123456...' 

// this is a list of index values to 

// look up in `x` in hexidecimal so that each 

// index is a single character

.split``

// split the index values into an array `[0xe, 0x2 ...`

.map(_=>j+=`x[0x${_}]+`)

// map over the index values and write a string like

// this `x[0xe]+x[0x2]+...` into `j`

console.log(eval(j+'""'))

// evaluate `j` with an empty string at the end

// `x[0xe]+x[0x2]+""` and log it out

const numbers = [1, 2, 3];

const letters = ['a', 'b', 'c'];

const symbols = ['!', '@', '#'];

// use spread operator

const combined = [...numbers, ...letters, ...symbols];

console.log('first', combined);

// older way

const combinedConcat = numbers

  .concat(letters)

  .concat(symbols);

console.log('second', combinedConcat);

const nums = [1, 10, 20, 30, 50, 88];

nums.sort(() => Math.random() - 0.5);

console.log(nums);