public/subjects/using-map.en.md

## Using Map

### Instructions

-Create a function named 'citiesOnly' which takes an array of objects
and which return an array of strings from the key `city`.

Example:

```js
[
  {
    city: 'Los Angeles',
    temperature: '  101 °F   ',
  },
  {
    city: 'San Francisco',
    temperature: ' 84 ° F   ',
  },
]
```

returns

```js
['Los Angeles', 'San Francisco']
```

-Create a function named 'upperCasingStates' which takes an array of strings
and which Upper Case each words of a string.
The function returns then an array of strings.

Example:
```js
['alabama', 'new jersey']
```
returns
```js
['Alabama', 'New Jersey']
```

-Create a function named 'fahrenheitToCelsius' which takes an array
of fahrenheit temperatures which converts them to Celsius.
Round down the result.

The function then returns the result as an array of strings like below:

example:
```js
['68°F', '59°F', '25°F']
```

returns
```js
['20°C', '15°C', '-4°C']
```


-Create a function named 'trimTemp' which takes an array of objects
and which removes the spaces from the string in the key `temperature`.
The function then returns an array of objects with the modification.

Example:
```js
[
  { city: 'Los Angeles', temperature: '  101 °F   '},
  { city: 'San Francisco', temperature: ' 84 ° F   '},
]
```

returns

```js
[
  { city: 'Los Angeles', temperature: '101°F' },
  { city: 'San Francisco', temperature: '84°F' },
]
```

-Create a 'tempForecasts' function which will take an array of objects, and which will
return an array of strings formatted as below:

```js
[
  {
    city: 'Pasadena',
    temperature: ' 101 °F',
    state: 'california',
    region: 'West',
  }
]
```

returns

```js
['38°Celsius in Pasadena, California']
```

### Notions

- [devdocs.io/javascript/global_objects/array/map](https://devdocs.io/javascript/global_objects/array/map)