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https://github.com/kucukkanat/localdb
MongoDB on the browser. A database using Javascript localStorage
https://github.com/kucukkanat/localdb
javascript javascript-localstorage localdb localdb-instance localstorage localstorage-adapter localstorage-api localstorage-wrapper
Last synced: 2 days ago
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MongoDB on the browser. A database using Javascript localStorage
- Host: GitHub
- URL: https://github.com/kucukkanat/localdb
- Owner: kucukkanat
- License: mit
- Created: 2015-10-25T20:44:26.000Z (over 9 years ago)
- Default Branch: master
- Last Pushed: 2022-12-03T03:27:35.000Z (about 2 years ago)
- Last Synced: 2024-04-14T22:12:34.329Z (10 months ago)
- Topics: javascript, javascript-localstorage, localdb, localdb-instance, localstorage, localstorage-adapter, localstorage-api, localstorage-wrapper
- Language: JavaScript
- Homepage:
- Size: 1.89 MB
- Stars: 74
- Watchers: 2
- Forks: 4
- Open Issues: 10
-
Metadata Files:
- Readme: Readme.MD
- Funding: .github/FUNDING.yml
- License: LICENSE
Awesome Lists containing this project
README
# A local database implementation using localStorage API
This is a simple wrapper for javascript's localStorage API for a more convenient use.
## Installation
```
yarn add local-db --dev
```
or
```
npm install local-db --save-dev
```
or
```
```
## Usage
```javascript
import LocalDB from 'local-db'
```
or
```javascript
var LocalDB = require('local-db')
```
then
```javascript
var usersTable = new LocalDB('users')
```
## Methods
### .create(object)
If object has an `.id` property, LocalDB will try to update the object in the table with
regarding id.
```javascript
usersTable.insert({username:'kucukkanat',city:'Izmir'})
```
**returns :** the user object created in table with generated ID
### .read(query)
Returns an array of the elements matching the query
```javascript
// Guys you are not allowed to buy cigarettes!
usersTable.query({age:{$lt:{18}}})
```
**returns :** the user object created in table with generated ID
### .update(query,object)
Updates all objects in table matching the query. The update method does a deep merge
using `lodash` 's `_.merge` method. [_.merge](https://lodash.com/docs/4.17.4#merge)
```javascript
// Moves kucukkanat from Izmir to Amsterdam
usersTable.update({username:'kucukkanat'},{city:'Amsterdam'})
```
**returns :** LocalDB instance itself
### .delete(query)
Deletes all objects in table matching the query
```javascript
// Are you not a bit old for skating grandpa ?
usersTable.delete({age:{$gt:70}})
```
**returns :** LocalDB instance itself
### .drop()
Empties the table
```javascript
usersTable.drop()
```
**returns :** LocalDB instance itself
### .on(eventName,fn)
Listens for events : `insert` , `create` , `update` , `remove` , `delete` , `drop`
```javascript
users.on('$insert',(object)=>{
// console.log(object, ' inserted!')
})
users.on('$delete',(object)=>{
// console.log(object, ' deleted!')
})
users.on('$update',(object,nextObject)=>{
console.log(object, ' updated to ',nextObject)
})
```
**returns :** LocalDB instance itself
## Supported Operators:
See MongoDB's [advanced queries](http://www.mongodb.org/display/DOCS/Advanced+Queries) for more info.
### $in
array value must be *$in* the given query:
Intersecting two arrays:
```javascript
//filtered: ['Brazil']
table.query({ $in: ['Costa Rica','Brazil'] }, ['Brazil','Haiti','Peru','Chile']);
```
Here's another example. This acts more like the $or operator:
```javascript
table.query({ location: { $in: ['Costa Rica','Brazil'] } }, [ { name: 'Craig', location: 'Brazil' } ]);
```
### $nin
Opposite of $in:
```javascript
//filtered: ['Haiti','Peru','Chile']
table.query({ $nin: ['Costa Rica','Brazil'] }, ['Brazil','Haiti','Peru','Chile']);
```
### $exists
Checks if whether a value exists:
```javascript
//filtered: ['Craig','Tim']
table.query({ $exists: true }, ['Craig',null,'Tim']);
```
You can also filter out values that don't exist
```javascript
//filtered: [{ name: 'Craig', city: 'Minneapolis' }]
table.query({ city: { $exists: false } }, [ { name: 'Craig', city: 'Minneapolis' }, { name: 'Tim' }]);
```
### $gte
Checks if a number is >= value:
```javascript
//filtered: [2, 3]
table.query({ $gte: 2 }, [0, 1, 2, 3]);
```
### $gt
Checks if a number is > value:
```javascript
//filtered: [3]
table.query({ $gt: 2 }, [0, 1, 2, 3]);
```
### $lte
Checks if a number is <= value.
```javascript
//filtered: [0, 1, 2]
table.query({ $lte: 2 }, [0, 1, 2, 3]);
```
### $lt
Checks if number is < value.
```javascript
//filtered: [0, 1]
table.query({ $lt: 2 }, [0, 1, 2, 3]);
```
### $eq
Checks if query == value. Note that **$eq can be omitted**. For **$eq**, and **$ne**
```javascript
//filtered: [{ state: 'MN' }]
table.query({ state: {$eq: 'MN' }}, [{ state: 'MN' }, { state: 'CA' }, { state: 'WI' }]);
```
Or:
```javascript
//filtered: [{ state: 'MN' }]
table.query({ state: 'MN' }, [{ state: 'MN' }, { state: 'CA' }, { state: 'WI' }]);
```
### $ne
Checks if query != value.
```javascript
//filtered: [{ state: 'CA' }, { state: 'WI'}]
table.query({ state: {$ne: 'MN' }}, [{ state: 'MN' }, { state: 'CA' }, { state: 'WI' }]);
```
### $mod
Modulus:
```javascript
//filtered: [300, 600]
table.query({ $mod: [3, 0] }, [100, 200, 300, 400, 500, 600]);
```
### $all
values must match **everything** in array:
```javascript
//filtered: [ { tags: ['books','programming','travel' ]} ]
table.query({ tags: {$all: ['books','programming'] }}, [
{ tags: ['books','programming','travel' ] },
{ tags: ['travel','cooking'] } ]);
```
### $and
ability to use an array of expressions. All expressions must test true.
```javascript
//filtered: [ { name: 'Craig', state: 'MN' }]
table.query({ $and: [ { name: 'Craig' }, { state: 'MN' } ] }, [
{ name: 'Craig', state: 'MN' },
{ name: 'Tim', state: 'MN' },
{ name: 'Joe', state: 'CA' } ]);
```
### $or
OR array of expressions.
```javascript
//filtered: [ { name: 'Craig', state: 'MN' }, { name: 'Tim', state: 'MN' }]
table.query({ $or: [ { name: 'Craig' }, { state: 'MN' } ] }, [
{ name: 'Craig', state: 'MN' },
{ name: 'Tim', state: 'MN' },
{ name: 'Joe', state: 'CA' } ]);
```
### $nor
opposite of or:
```javascript
//filtered: [ { name: 'Tim', state: 'MN' }, { name: 'Joe', state: 'CA' }]
table.query({ $nor: [ { name: 'Craig' }, { state: 'MN' } ] }, [
{ name: 'Craig', state: 'MN' },
{ name: 'Tim', state: 'MN' },
{ name: 'Joe', state: 'CA' } ]);
```
### $size
Matches an array - must match given size:
```javascript
//filtered: ['food','cooking']
table.query({ tags: { $size: 2 } }, [ { tags: ['food','cooking'] }, { tags: ['traveling'] }]);
```
### $type
Matches a values based on the type
```javascript
table.query({ $type: Date }, [new Date(), 4342, 'hello world']); //returns single date
table.query({ $type: String }, [new Date(), 4342, 'hello world']); //returns ['hello world']
```
### $regex
Matches values based on the given regular expression
```javascript
table.query({ $regex: /^f/i, $nin: ["frank"] }, ["frank", "fred", "sam", "frost"]); // ["fred", "frost"]
table.query({ $regex: "^f", $options: "i", $nin: ["frank"] }, ["frank", "fred", "sam", "frost"]); // ["fred", "frost"]
```
### $where
Matches based on some javascript comparison
```javascript
table.query({ $where: "this.name === 'frank'" }, [{name:'frank'},{name:'joe'}]); // ["frank"]
table.query({
$where: function() {
return this.name === "frank"
}
}, [{name:'frank'},{name:'joe'}]); // ["frank"]
```
### $elemMatch
Matches elements of array
```javascript
var bills = [{
month: 'july',
casts: [{
id: 1,
value: 200
},{
id: 2,
value: 1000
}]
},
{
month: 'august',
casts: [{
id: 3,
value: 1000,
}, {
id: 4,
value: 4000
}]
}];
var result = table.query({
casts: {$elemMatch:{
value: {$gt: 1000}
}}
}, bills); // {month:'august', casts:[{id:2, value: 1000},{id: 4, value: 4000}]}
```
### $not
Not expression:
```javascript
table.query({$not:{$in:['craig','tim']}}, ['craig','tim','jake']); //['jake']
table.query({$not:{$size:5}}, ['craig','tim','jake']); //['tim','jake']
```
## sub object Searching
```javascript
var people = [{
name: 'craig',
address: {
city: 'Minneapolis'
}
},
{
name: 'tim',
address: {
city: 'St. Paul'
}
}];
var queried = table.query({ address: { city: 'Minneapolis' }}, people); // count = 1
//or
var queried = table.query({'address.city': 'minneapolis'}, people);//count = 1
```