30-seconds-of-code
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A collection of useful JavaScript snippets.
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Markdown
### mapString
Creates a new string with the results of calling a provided function on every character in the calling string.
Use `String.split('')` and `Array.map()` to call the provided function, `fn`, for each character in `str`.
Use `Array.join('')` to recombine the array of characters into a string.
The callback function, `fn`, takes three arguments (the current character, the index of the current character and the string `mapString` was called upon).
```js
const mapString = (str, fn) =>
str
.split('')
.map((c, i) => fn(c, i, str))
.join('');
```
```js
mapString('lorem ipsum', c => c.toUpperCase()); // 'LOREM IPSUM'
```