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Update README.md #107

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Update README.md
kamil-kielczewski Aug 31, 2020
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kamil-kielczewski Sep 1, 2020
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kamil-kielczewski Sep 1, 2020
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Expand Up @@ -463,6 +463,27 @@ which after removing the comma (by using [multi-arguments technique](#calling-me
["pattern"]["concat"]("g")["reduce"]([]["fill"]["constructor"]("return RegExp")())
```

# (un)escape - gate for all

Having following characters: `123456789 aceflnmoprstu` (which can be acheved one by one) we are able to get other lower/upper case letters and some characters without using deprecated methods like [italics](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/italics). Deprecated methods was used in jsfuck for size-optimizations. To avoid them we can use `escape` and `unescape` methods - technique base on this [forum (2013)](https://news.ycombinator.com/item?id=6379732). We can do it by e.g. for letter `C` (which has hexadecimal escape code 43) as follows (we show 5 steps of formula evolution towards jsf)

```js
step1: unescape("%43")
step2: unescape(escape(" ")[0]+43)
step3: unescape(escape((NaN+[]["flat"])[11])[0]+43)
step4: Function("return unescape")()(Function("return escape")()(" ")[0]+43)
step5: []["flat"]["constructor"]("return unescape")()([]["flat"]["constructor"]("return escape")()((NaN+[]["flat"])[11])[0]+43)
```

Using this approach we have access to: `!"#$%&'()*+,-./0123456789:;<=>?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\]^_ abcdefghijklmnopqrstuvwxyz{|}~` + tilde character and more. Using this technique we don't need to use `String.fromCharCode` (which in old approach forced to use deprecated methods like 'italics' or 'fontcolor' etc.)

For letter "C" we can also use below shortcut based on `escape` only discovered by [Siguza](https://stackoverflow.com/a/63675158/860099)
```js
step1: Function("return escape")()(",")[2]
step2: []["flat"]["constructor"]("return escape")()([[]]["concat"]([[]])+[])[2]
```


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# Alternatives
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