# JavaScript Tips

### Javascript/NPM/Yarn

#### Yarn: Update Packages Globally

```
yarn global upgrade-interactive
```

**Yarn: Fix missing/bad signature issue**

```
curl -sS https://dl.yarnpkg.com/debian/pubkey.gpg | sudo apt-key add -
```

#### NPM: Update Packages Globally

```
npm i npm-check -g
```

```
npm-check -gu
```

#### JS: Fake Geolocation Data

```
navigator.geolocation.getCurrentPosition = function(success, failure) { 
    success({ coords: { 
        latitude: 42.3143286, 
        longitude: -71.0403234

    }, timestamp: Date.now() }); 
}
```

#### JS: Flatten multiple arrays

```
let arrays = [
  ["$6"],
  ["$12"],
  ["$25"],
  ["$25"],
  ["$18"],
  ["$22"],
  ["$10"]
];

let merged = [].concat.apply([], arrays);
```

#### JS: Get only unique values in array (ala PHP’s array\_unique)

```
[ ...new Set(array) ]
```