2b:null 2c:["$","title",null,{"children":"LokiJS database. | Brett Cooper | Observable"}] 31:T47d,html`

LokiJS database.

http://techfort.github.io/LokiJS/ - techfort/LokiJS/wiki - LokiJS/blob/master/OVERVIEW.md

A database db is instantiated called sandbox.db.

A collection is connected to the database. items of a db.

Items are inserted into the collection, it doesn't mater if they already exist they will be added again each time the insert is run.

Looking at the docs, I see LokiLocalStorageAdapter is what i need to use to load and save the database.
Load and save example https://github.com/techfort/LokiJS/blob/master/examples/quickstart4.js

The web browser's local storage object size 5242769 bytes.

web.dev/native-file-system Looks like it could be used for larger databases.

`32:Tab5,html`

TODO:

`33:Ta88,html`

Open a database called sandbox.

new Loki(filename, optionsopt) Instaniciate the database

filename, type string, the name of the file to be saved to.
options, type object optional, config options object

Returns: The main database class.

Parameters:

Name	Type	Attributes	Default	Description
env	string			override environment detection as 'NODEJS', 'BROWSER', 'CORDOVA'
verbose	boolean	optional	false	enable console output
autosave	boolean	optional	false	enables autosave
autosaveInterval	int	optional	5000	time interval (in milliseconds) between saves (if dirty)
autoload	boolean	optional	false	enables autoload on loki instantiation
autoloadCallback	function			user callback called after database load
adapter	adapter			an instance of a loki persistence adapter
serializationMethod	string	optional	'normal'	'normal', 'pretty', 'destructured'
destructureDelimiter	string			string delimiter used for destructured serialization
throttledSaves	boolean	optional	true	debounces multiple calls to to saveDatabase reducing number of disk I/O operations and guaranteeing proper serialization of the calls

`34:Ta95,html`

Add some Entries/Trupils to the database.

addCollection(name, options) Adds a collection to the database.

name: type string - "collection name".
options: type array | object - (optional) array of property names to be indicized OR a configuration object.
Returns: Database Collection Table for use. Type: Object

Parameters:

Name	Type	Attributes	Default	Description
unique	array	optional	[ ]	array of property names to define unique constraints for
exact	array	optional	[ ]	array of property names to define exact constraints for
indices	array	optional	[ ]	array property names to define binary indexes for
asyncListeners	boolean	optional	false	whether listeners are called asynchronously
disableMeta	boolean	optional	false	set to true to disable meta property on documents
disableChangesApi	boolean	optional	true	set to false to enable Changes Api
disableDeltaChangesApi	boolean	optional	true	set to false to enable Delta Changes API (requires Changes API, forces cloning)
autoupdate	boolean	optional	false	use Object.observe to update objects automatically
clone	boolean	optional	false	specify whether inserts and queries clone to/from user
cloneMethod	string	optional	'parse-stringify'	'parse-stringify', 'jquery-extend-deep', 'shallow, 'shallow-assign'
ttl	int	optional		age of document (in ms.) before document is considered aged/stale.
ttlInterval	int	optional		time interval for clearing out 'aged' documents; not set by default.

`35:T4ab,html`

insert(doc) → { object | array }

Adds object(s) to collection, ensure object(s) have meta properties, clone it if necessary, etc.

Returns: document or documents inserted: Type: object | array[object...]

Name	Type	Description
doc	object / array	the document (or array of documents) to be inserted

Example:
   users.insert({name: 'Odin', age: 50, address: Asgard'});
   // alternatively, insert array of documents
   users.insert([{name: 'Thor', age: 35}, {name: 'Loki',age: 30}]);

`36:T5d2,where_query = html`

Query if 'something' is in the Database

where(filter_function) → {array}

Query the collection by supplying a javascript filter function.

Returns: all documents which pass your query filter Function. Type: array

Parameters:

Name	Type	Description
filter_function	function	filter function to run against all collection docs

Examples: LokiJS/tutorial Query Examples.html

 // simple anonymous filter
 var results = te_items.where(function(obj) {
 return obj.name === "Bob";
 });

 // -or- set up named filter function
 function BobFilter(obj) { return obj.name === 'Bob'; }

 // and then pass that
 results = te_items.where(BobFunction);

`37:T2864,md`# poop ~~~js $eq - filter for document(s) with property of (strict) equality // implicit (assumes $eq operator) var results = coll.find({'Name': 'Odin'}); // explicit $eq results = coll.find({'Name': { '$eq' : 'Odin' }}); $ne - filter for document(s) with property not equal to provided value // not equal test var results = coll.find({'legs': { '$ne' : 8 }}); $aeq - filter for document(s) with property of abstract (loose) equality // will match documents with age of '20' or 20 var results = coll.find(age: {$aeq: 20}); $dteq - filter for document(s) with date property equal to provided date value var dt1 = new Date("1/1/2017"); var dt2 = new Date("1/1/2017"); items.insert({ name : 'mjolnir', created: dt1 }); items.insert({ name : 'gungnir', created: dt2 }); // returns both of the above inserted documents var results = items.find({ created: { $dteq: new Date("1/1/2017") } }); $gt - filter for document(s) with property greater than provided value var results = coll.find({'age': {'$gt': 40}}); $gte - filter for document(s) with property greater or equal to provided value var results = coll.find({'age': {'$gte': 40}}); $lt - filter for document(s) with property less than provided value var results = coll.find({'age': {'$lt': 40}}); $lte - filter for document(s) with property less than or equal to provided value var results = coll.find({'age': {'$lte': 40}}); $between - filter for documents(s) with property between provided vals // match users with count value between 50 and 75 var results = users.find({ count : { '$between': [50, 75] }}); > Note : the above $gt, $gte, $lt, $lte, and $between ops use 'loki' sorting which provides a unified range actoss mixed types and which return the same results whether the property is indexed or not. This is needed for binary indexes and for guarantees of results equality between indexed and non-indexed comparisons. If you do not expect to utilize a binary index and you expect that simple javascript comparisons are acceptable, we provide the following ops which (due to their simplified comparisons) may provide more optimal execution speeds. $jgt - filter (using simplified javascript comparison) for docs with property greater than provided value var results = coll.find({'age': {'$jgt': 40}}); $jgte - filter (using simplified javascript comparison) for docs with property greater than or equal to provided value var results = coll.find({'age': {'$jgte': 40}}); $jlt - filter (using simplified javascript comparison) for docs with property less than provided value var results = coll.find({'age': {'$jlt': 40}}); $jlte - filter (using simplified javascript comparison) for docs with property less than or equal to provided value var results = coll.find({'age': {'$jlte': 40}}); $jbetween - filter (using simplified javascript comparison) for docs with property between provided vals var results = users.find({ count : { '$jbetween': [50, 75] }}); $regex - filter for document(s) with property matching provided regular expression If using regex operator within a named transform or dynamic view filter, it is best to use the latter two examples since raw regex does not seem to serialize/deserialize well. // pass in raw regex var results = coll.find({'Name': { '$regex' : /din/ }}); // or pass in string pattern only results = coll.find({'Name': { '$regex': 'din' }}); // or pass in [pattern, options] string array results = coll.find({'Name': { '$regex': ['din', 'i'] }}); $in - filter for document(s) with property matching any of the provided array values. Your property should not be an array but your compare values should be. users.insert({ name : 'odin' }); users.insert({ name : 'thor' }); users.insert({ name : 'svafrlami' }); // match users with name in array set ['odin' or 'thor'] var results = users.find({ 'name' : { '$in' : ['odin', 'thor'] } }); $nin - filter for document(s) with property not matching any of the provided array values. users.insert({ name : 'odin' }); users.insert({ name : 'thor' }); users.insert({ name : 'svafrlami' }); // match users with name not in array set ['odin' or 'thor'] (svafrlami doc only) var results = users.find({ 'name' : { '$nin' : ['odin', 'thor'] } }); $keyin - filter for document(s) whose property value is defined in the provided hash object keys. (Equivalent to $in: Object.keys(hashObject)) ( #362, #365 ) categories.insert({ name: 'Title', column: 'title'}) // since the op doesn't use the title value, this is most effective with existing objects var result = categories.find({column: { $keyin: { title: 'anything'} }}); $nkeyin - filter for document(s) whose property value is not defined in the provided hash object keys. (Equivalent to $nin: Object.keys(hashObject)) ( #362, #365 ) var result = categories.find({column: { $nkeyin: { title: 'anything'} }}); $definedin - filter for document(s) whose property value is defined in the provided hash object as a value other than undefined. #285 items.insert({ name : 'mjolnir', owner: 'thor', maker: 'dwarves' }); items.insert({ name : 'gungnir', owner: 'odin', maker: 'elves' }); items.insert({ name : 'tyrfing', owner: 'Svafrlami', maker: 'dwarves' }); items.insert({ name : 'draupnir', owner: 'odin', maker: 'elves' }); // returns gungnir and draupnir. similar to $keyin, the value ('rule') is not used by the op var results = items.find({maker: { $efinedin: { elves: 'rule' } } }); $undefinedin - filter for document(s) whose property value is not defined in the provided hash object or defined but is undefined. #285 items.insert({ name : 'mjolnir', owner: 'thor', maker: 'dwarves' }); items.insert({ name : 'gungnir', owner: 'odin', maker: 'elves' }); items.insert({ name : 'tyrfing', owner: 'Svafrlami', maker: 'dwarves' }); items.insert({ name : 'draupnir', owner: 'odin', maker: 'elves' }); // returns mjolnir and tyrfing where the 'dwarves' val is not a property on our passed object var results = items.find({maker: { $undefinedin: { elves: 'rule' } } }); $contains - filter for document(s) with property containing the provided value. ( commit, #205 ). Use this when your property contains an array but your compare value is not an array. When typeof property is : string: it will do a substring match for your string (indexOf) array: it will check for 'value' existence in that array (indexOf) object: it will check to see if your 'value' is a defined property of that object users.insert({ name : 'odin', weapons : ['gungnir', 'draupnir']}); users.insert({ name : 'thor', weapons : ['mjolnir']}); users.insert({ name : 'svafrlami', weapons : ['tyrfing']}); users.insert({ name : 'arngrim', weapons : ['tyrfing']}); // returns 'svafrlami' and 'arngrim' documents var results = users.find({ 'weapons' : { '$contains' : 'tyrfing' } }); $containsAny - filter for document(s) with property containing any of the provided values. Use this when your property contains an array -and- your compare value is an array. When typeof property is : string: it will do a substring match for your string (indexOf) array: it will check for 'value' existence in that array (indexOf) object: it will check to see if your 'value' is a defined property of that object javascript users.insert({ name : 'odin', weapons : ['gungnir', 'draupnir']}); users.insert({ name : 'thor', weapons : ['mjolnir']}); users.insert({ name : 'svafrlami', weapons : ['tyrfing']}); users.insert({ name : 'arngrim', weapons : ['tyrfing']}); // returns 'svafrlami', 'arngrim', and 'thor' documents results = users.find({ 'weapons' : { '$containsAny' : ['tyrfing', 'mjolnir'] } }); **$containsNone** - filter for documents(s) with property containing none of the provided values users.insert({ name : 'odin', weapons : ['gungnir', 'draupnir']}); users.insert({ name : 'thor', weapons : ['mjolnir']}); users.insert({ name : 'svafrlami', weapons : ['tyrfing']}); users.insert({ name : 'arngrim', weapons : ['tyrfing']}); // returns 'svafrlami' and 'arngrim' results = users.find({ 'weapons' : { '$containsNone' : ['gungnir', 'mjolnir'] } }); $type - filter for documents which have a property of a specified type users.insert([ { name: 'odin', weapons: ['gungnir', 'draupnir'] }, { name: 'thor', weapons: 'mjolnir' }, { name: 'svafrlami', weapons: ['tyrfing'] }, { name: 'arngrim', weapons: ['tyrfing'] } ]); // returns docs with (non-array) string value for 'weapons' (mjolnir) var results = users.find({ 'weapons' : { '$type' : 'string' } }); $finite - filter for documents with property which is numeric or non-numeric. // return all docs where isFinite(doc.age) === true var results = users.find({ age: { $finite: true }}); $size - filter for documents which have array property of specified size. (does not work for strings) users.insert([ { name: 'odin', weapons: ['gungnir', 'draupnir'] }, { name: 'thor', weapons: 'mjolnir' }, { name: 'svafrlami', weapons: ['tyrfing'] }, { name: 'arngrim', weapons: ['tyrfing'] } ]); // returns docs where 'weapons' are 2-element arrays (odin) var results = users.find({ 'weapons' : { '$size' : 2 } }); $len - filter for documents which have string property of specified length. users.insert([ { name: 'odin', weapons: ['gungnir', 'draupnir'] }, { name: 'thor', weapons: 'mjolnir' }, { name: 'svafrlami', weapons: ['tyrfing'] }, { name: 'arngrim', weapons: ['tyrfing'] } ]); // returns docs where 'name' is a 9 character string (svafrllami) var results = users.find({ 'name' : { '$len' : 9 } }); $and - filter for documents which meet all nested subexpressions // fetch documents matching both sub-expressions var results = coll.find({ '$and': [{ 'age' : { '$gt': 30 } },{ 'name' : 'Thor' }] }); // alternative 'implicit' syntax : results = coll.find({ age: { $gt: 30 }, name: 'Thor' }); $or - filter for documents which meet any of the nested subexpressions // fetch documents matching any of the sub-expressions var results = coll.find({ '$or': [{ 'age' : { '$gte': '40' } },{ 'name' : 'Thor' }] }); $exists - filter for documents which contain (even when the value is null) this field or not // fetch documents which do not have this field. Use '$exists': true for documents which have this field (it may be null) var results = coll.find({ 'age': { '$exists': false } }); ~~~ `38:[] 2f:{"id":"a0423eee08df1385","slug":"lokijs-database","title":"LokiJS database.","thumbnail":"18fd6f7d89fa6f75579315ba00cb67511594885ce25ff5b7ffa20c51b81831f0","access_level":"public","create_time":"$D2020-08-31T09:37:49.791Z","update_time":"$D2022-02-07T02:41:25.787Z","view_time":null,"first_public_time":"$D2020-09-05T07:51:53.532Z","fork":false,"stars":0,"starred":false,"owner":{"type":"team","id":"ca35562412a365ec","login":"hellonearthis","name":"Brett Cooper","avatar_url":"https://avatars-next.observableusercontent.com/ee05023c4c2a9d53e29a4f85f35e35430ae16d2c4aa6a6ca791175caf667abc2","tier":"starter_2024"},"version":1139,"publish_version":1139,"role":null,"authored":false,"authors":[{"type":"individual","id":"71df97e2192b6fce","login":"hellonearthis","name":"Brett Cooper","avatar_url":"https://avatars-next.observableusercontent.com/ee05023c4c2a9d53e29a4f85f35e35430ae16d2c4aa6a6ca791175caf667abc2","tier":null}],"members":[{"type":"individual","id":"71df97e2192b6fce","login":"hellonearthis","name":"Brett Cooper","avatar_url":"https://avatars-next.observableusercontent.com/ee05023c4c2a9d53e29a4f85f35e35430ae16d2c4aa6a6ca791175caf667abc2","tier":null,"role":"editor"}],"comments":[],"custom_thumbnail":false,"trashed":false,"subscribed":null,"forks":1,"collection":null,"type":"notebook","body":{"title":"LokiJS database.","cells":[{"id":277,"value":"$31","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined"},{"id":760,"value":"$32","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined"},{"id":869,"value":"md`---`","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined"},{"id":308,"value":"$33","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined"},{"id":59,"value":"db = new loki('sandbox.db')","pinned":true,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined"},{"id":314,"value":"$34","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined"},{"id":67,"value":"mutable te_items = db.addCollection('items');","pinned":true,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined"},{"id":324,"value":"$35","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined"},{"id":842,"value":"md`---\n# Add an entry to the database.`","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined"},{"id":821,"value":"items = form(html``)","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined"},{"id":829,"value":"add_form_to_database = html``","pinned":true,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined"},{"id":565,"value":"Add_One_entery_to_the_database = html``","pinned":true,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined"},{"id":704,"value":"Add_4_items_to_DB = md`# I want to only add these items if they are not in the database.\n\nAnd if they are in the database, check to see if stuff has changed and update if needed. `","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined"},{"id":782,"value":"viewof addData = html``","pinned":true,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined"},{"id":27,"value":"// Insert some documents to the collection\n// needs to test that these are present\nadd_data = {\n addData; // run again when the button is clicked\n mutable te_items.insert({ name : 'mjolnir', owner: 'thor', maker: 'dwarves' });\n mutable te_items.insert({ name : 'gungnir', owner: 'odin', maker: 'elves' });\n mutable te_items.insert({ name : 'tyrfing', owner: 'Svafrlami', maker: 'dwarves' });\n mutable te_items.insert({ name : 'draupnir', owner: 'odin', maker: 'elves' });\n mutable te_items = mutable te_items; // trigger downstream cells\n}","pinned":true,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined"},{"id":636,"value":"te_items.data","pinned":true,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined"},{"id":957,"value":"$36","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined"},{"id":950,"value":"where_results = {\n wheres_bob;\n return te_items.where(function(obj) {\n return obj.name === \"Bob\";\n });\n}","pinned":true,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined"},{"id":981,"value":"viewof wheres_bob = html``","pinned":true,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined"},{"id":231,"value":"html`

findOne(query) → {object|null}

\n\n\n\n

Find one object by index property, by property equal to value.

Returns: First matching document, or null if none. Type: object | null

\n Parameters:\n\n\n\n\n\n

Name	Type	Description
query	object	query object used to perform search with

\n\n`","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined"},{"id":775,"value":"viewof doThis = html``","pinned":true,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined"},{"id":76,"value":"find = {\n add_data; // depends on add_data inserting tyrfing\n doThis;\n var tyrfing = mutable te_items.findOne({'name': 'tyrfing'});\n tyrfing.owner = 'todd';\n mutable te_items.update(tyrfing);\n mutable te_items = mutable te_items;\n}","pinned":true,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined"},{"id":725,"value":"md`---\n# appendix\nHuge thanks to Mike for his help. https://talk.observablehq.com/t/trying-to-see-when-database-content-has-changed/3838/2\n

\nother bits of data used to make this...\n---`","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined"},{"id":8,"value":"loki = require('lokijs@1.5.11/src/lokijs.js').catch(() => window[\"loki\"])","pinned":true,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined"},{"id":13,"value":"md`Might also want to use **lokijs.min.js**\n\n[*From module debugger:*](https://observablehq.com/@observablehq/module-require-debugger)
\nThe ‘global leak’ pattern. It’s a doozy. Essentially a module that works in node, and works as a script tag, but doesn’t work with any specific loader. So we use require(), expect it to fail, and then grab the global that it adds to the window. There may be multiple variables attached to the window that way, so for completeness, here are all of them: loki.`","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined"},{"id":300,"value":"import {html, svg} from \"@observablehq/htl\"","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined"},{"id":823,"value":"import {form} from \"@mbostock/form-input\"","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined"},{"id":450,"value":"","pinned":false,"hidden":false,"mode":"html","author":"$undefined","summary":"$undefined"},{"id":885,"value":"md`# Find query\n**This, when html styled is too big for a cell :0**\nThe primary operators currently supported are :\n`\n","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined"},{"id":1110,"value":"html``","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined"},{"id":1116,"value":"$37","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined"}],"files":"$W38","stdlib":"1","titling":"auto"}} 30:"$2f:body"