https://github.com/jclem/steeltoe

Don't shoot yourself in the foot traversing objects.
https://github.com/jclem/steeltoe

Last synced: about 2 months ago
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Don't shoot yourself in the foot traversing objects.

• Host: GitHub
• URL: https://github.com/jclem/steeltoe
• Owner: jclem
• License: mit
• Created: 2012-10-26T17:08:48.000Z (almost 12 years ago)
• Default Branch: master
• Last Pushed: 2014-02-25T09:09:54.000Z (over 10 years ago)
• Last Synced: 2024-07-26T20:59:00.440Z (2 months ago)
• Language: JavaScript
• Homepage: https://www.npmjs.org/package/steeltoe
• Size: 202 KB
• Stars: 94
• Watchers: 8
• Forks: 9
• Open Issues: 2
• Metadata Files:
  • Readme: README.md
  • License: LICENSE.md

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README

        
# [SteelToe](http://jclem.github.io/steeltoe/)

Don't shoot yourself in the foot while traversing JavaScript objects.

## Get It

```sh

$ npm install steeltoe --save

```

## Usage

SteelToe is a tiny JavaScript function that makes it safe to traipse about

objects without worrying about whether keys may or may not exist, and whether

it's safe to try and look inside of them. It also provides basic

[autovivification](http://en.wikipedia.org/wiki/Autovivification) of objects

through the `set` function.

### Getting Values

#### Method #1

```javascript

var object = { info: { name: { first: 'Jonathan', last: 'Clem' } } }

steelToe(object)('info')('name')('last')();           // 'Clem'

steelToe(object)('info')('features')('hairColor')();  // undefined

```

#### Method #2

```javascript

var object = { info: { name: { first: 'Jonathan', last: 'Clem' } } }

steelToe(object).get('info.name.last');          // 'Clem'

steelToe(object).get('info.features.hairColor'); // undefined

```

### Setting Values

```javascript

var jonathan = { info: { name: { first: 'Jonathan', last: 'Clem' } } },

steelToe(jonathan).set('info.name.middle', 'Tyler');

steelToe(jonathan).set('info.favorites.movie', 'Harold & Maude');

jonathan.info.name.middle; // Tyler

jonathan.info.favorites.movie; // Harold & Maude

````

## Details

Let's say you've got some deeply nested data in JavaScript objects that you've

just parsed from a JSON API response. For each result, you need to do something

if there's some sort of data present:

```javascript

var fatherFirstNames = [];

for (var i = 0; i < families.length; i ++) {

  var first = families[i].father.info.name.first;

  if (first) {

    fatherFirstNames.push(first);

  }

}

// TypeError: 'undefined' is not an object (evaluating 'family.father.info.name.first')

```

Whoops! You shot yourself in the foot. You got a `TypeError` because you had no

guarantee that the family had a father, or that the father had info present, or

that his name was returned! You fix it by writing this monstrosity:

```javascript

var farherFirstNames = [];

for (var i = 0; i < families.length; i++) {

  var father = families[i].father;

  if (father && father.info && father.info.name && father.info.name.first) {

    fatherFirstNames.push(father.info.name.first);

  }

}

```

Or, you could use SteelToe and write this:

```javascript

var fatherFirstNames = [];

for (var i = 0; i < families.length; i++) {

  var name = steelToe(families[i]).get('father.info.name.first');

  if (name) {

    fatherFirstNames.push(name);

  }

}

fatherFirstNames; // ["Hank", "Dale", "Bill"]

```

## The End

SteelToe was made when a coworker of mine said that he wished someone would

write a JavaScript library that would allow him to traverse objects without

shooting himself in the foot, and that the library was called SteelToe.