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<!DOCTYPE html>  <html lang="en"> <head> <meta charset="utf-8"> <title>CanJS - can-set</title> <meta name="viewport" content="width=device-width, initial-scale=1, maximum-scale=1, user-scalable=no"> <link rel="stylesheet" type="text/css" href="./static/bundles/bit-docs-site/static.css"> <link rel="shortcut icon" sizes="16x16 24x24 32x32 48x48 64x64" href="/docs/images/canjs_favicon.ico"> <link rel="apple-touch-icon" sizes="57x57" href="../docs/images/canjs_favicon_57x57.png"> <link rel="apple-touch-icon-precomposed" sizes="57x57" href="../docs/images/canjs_favicon_57x57.png"> <link rel="apple-touch-icon" sizes="72x72" href="../docs/images/canjs_favicon_72x72.png"> <link rel="apple-touch-icon" sizes="114x114" href="../docs/images/canjs_favicon_114x114.png"> <link rel="apple-touch-icon" sizes="120x120" href="../docs/images/canjs_favicon_128x128.png"> <link rel="apple-touch-icon" sizes="144x144" href="../docs/images/canjs_favicon_144x144.png"> <link rel="apple-touch-icon" sizes="152x152" href="../docs/images/canjs_favicon_152x152.png"> <meta content="yes" name="apple-mobile-web-app-capable"> <meta name="apple-mobile-web-app-status-bar-style" content="white-translucent"> <script> (function(i,s,o,g,r,a,m){i['GoogleAnalyticsObject']=r;i[r]=i[r]||function(){ (i[r].q=i[r].q||[]).push(arguments)},i[r].l=1*new Date();a=s.createElement(o), m=s.getElementsByTagName(o)[0];a.async=1;a.src=g;m.parentNode.insertBefore(a,m) })(window,document,'script','https://www.google-analytics.com/analytics.js','ga'); ga('create', 'UA-2302003-11', 'auto'); ga('send', 'pageview'); </script> </head> <body> <input type="checkbox" id="nav-trigger" class="nav-trigger"/> <label for="nav-trigger">Menu</label> <div id="everything"> <div id="left" class="column"> <div class="top-left"> <div class="brand"> <div class="logo"> <a href="../index.html" alt="CanJS"></a> <div class="dropdown project-dropdown"> <a href="https://donejs.com/">DoneJS</a> <a href="http://stealjs.com/">StealJS</a> <a href="http://jquerypp.com/">jQuery ++</a> <a href="https://funcunit.com/">FuncUnit</a> <a href="http://documentjs.com/">DocumentJS</a> </div> </div> <div class="version"> <div class="version-number"> 3.0.0 </div> <div class="dropdown version-dropdown"> <a href="https://v2.canjs.com">2.3.27</a> </div> </div> </div> <div class="search-bar"> <p>   </p> </div> </div> <div class="bottom-left"> <div class="social-side-container"> <ul class="social-side"> <li> <a class="header-mobile github" href="https://github.com/canjs/canjs" target="_blank"><img class="social-icon-small" src="../docs/images/github.png">Github</a> </li> <li> <a class="header-mobile twitter" href="https://twitter.com/canjs" target="_blank"><img class="social-icon-small" src="../docs/images/twitter.png">Twitter</a> </li> </ul> <ul class="social-side"> <li> <a class="header-mobile" href="https://gitter.im/canjs/canjs" target="_blank">Chat</a> </li> <li> <a class="header-mobile" href="http://forums.donejs.com/c/canjs" target="_blank">Forum</a> </li> </ul> </div> <ul> <li class=" "> <a class="page" href="guides.html" title="Welcome to CanJS! 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The following functions create compares objects that can be mixed together to create a set Algebra. var set = require("can-set"); var algebra = new set.Algebra( { // ignore this property in set algebra sessionId: function(){ return true } }, set.props.boolean("completed"), set.props.rangeInclusive("start","end") );"> props </a> </li> </ul> </li> </ul> </li> <li class=" "> <a class="module" href="can-stache.html" title="Live binding Mustache and Handlebars-compatible templates."> can-stache </a> </li> <li class=" "> <a class="module" href="can-stache/helpers/route.html" title="Adds stache helpers that use can-route."> can-stache/helpers/route </a> </li> <li class=" "> <a class="module" href="can-stache-bindings.html" title="Provides template event, one-way, and two-way bindings."> can-stache-bindings </a> </li> </ul> </li> <li class=" "> <a class="page" href="can-ecosystem.html" title="Useful libraries that extend or add important features to the core collection."> Ecosystem </a> </li> <li class=" "> <a class="page" href="can-infrastructure.html" title="Utility libraries that power the core and ecosystem collection."> Infrastructure </a> </li> <li class=" "> <a class="page" href="can-legacy.html" title="Former libraries that we still accept patches for, but are not under active development."> Legacy </a> </li> </ul> </div> </div> <div id="right" class="column"> <div class="top-right"> <div class="top-right-top"> <ul class="top-right-bitovi"> <li class="dropdown"> <a href="http://bitovi.com" class="bitovi icon-bits">Bitovi</a> <ul class="dropdown-menu"> <li><a href="http://bitovi.com">Bitovi.com</a></li> <li><a href="http://bitovi.com/blog/">Blog</a></li> <li><a href="http://bitovi.com/consulting/">Consulting</a></li> <li><a href="http://bitovi.com/training/">Training</a></li> <li><a href="http://bitovi.com/open-source/">Open Source</a></li> </ul> </li> </ul> <div class="brand"> <div class="logo"> <a href="../index.html" alt="CanJS"></a> </div> </div> <ul class="top-right-links"> <li> <a href="https://gitter.im/canjs/canjs">Chat</a> </li> <li> <a href="http://forums.donejs.com/c/canjs">Forum</a> </li> <li> <a class="github-button nav-social" href="https://github.com/canjs/canjs" data-count-href="/canjs/canjs/stargazers" data-count-api="/repos/canjs/canjs#stargazers_count">Star</a> </li> <li> <a href="https://twitter.com/canjs" class="twitter-follow-button nav-social" data-show-count="true" data-show-screen-name="false">Follow @canjs</a><script async src="//platform.twitter.com/widgets.js" charset="utf-8"></script> </li> </ul> </div> <div class="breadcrumb"> <li><a href="../index.html">CanJS</a></li> / <li><a href="can-core.html">Core</a></li> / <li><a href="can-set.html">can-set</a></li> <li class="breadcrumb-dropdown">/ <a> On this page</a> <ul class="on-this-page"></ul> </li> <div class="nav-toggle" title="Back to top"></div> </div> </div> <div class="bottom-right"> <article> <section class="title"> <div class="page-type"> <h1>can-set</h1> <div>module</div> </div> <section class="description"> <p>can-set is a utility for comparing <a href="can-set/Set.html" title="An object that represents a set of data.">sets</a> that are represented by the parameters commonly passed to service requests.</p> </section> </section> <section class="on-this-page-table"> </section> <section class="title-footer"> <ul class="title-social"> <li> <a class="npm-button" href="https://www.npmjs.com/package/can-set"> <img src="https://img.shields.io/badge/npm%20package-1.0.2-brightgreen.svg" alt="npm package badge" /> </a> </li> <li> <a class="github-button nav-social" href="https://github.com/canjs/can-set" data-count-href="/canjs/can-set/stargazers" data-count-api="/repos/canjs/can-set#stargazers_count">Star</a> </li> </ul> <ul class="title-links">  <li><a href="//github.com/canjs/can-set/tree/v1.0.2/docs/can-set.md">source</a></li>   </ul> </section> <div class="signature"> <h2 class="signature-title"> <code>Object</code> </h2> <p>Once you've imported the <code>can-set</code> module into your project, use it to create a <code>set.Algebra</code> and then use that to compare and perform operations on sets.</p> <pre><code class="language-js">var set = require('can-set'); // create an algebra var algebra = new set.Algebra( // specify the unique identifier on data set.props.id("_id"), // specify that completed can be true, false or undefined set.props.boolean("completed"), // specify properties that define pagination set.props.rangeInclusive("start","end"), // specify the property that controls sorting set.props.sort("orderBy"), ) // compare two sets algebra.subset({start: 2, end: 3}, {start: 1, end: 4}) //-> true algebra.difference({} , {completed: true}) //-> {completed: false} // perform operations on sets algebra.getSubset({start: 2,end: 3},{start: 1,end: 4}, [{id: 1},{id: 2},{id: 3},{id: 4}]) //-> [{id: 2},{id: 3}] </code></pre> </div> <section class="body"> <h2>Use</h2> <p>A <a href="can-set/Set.html" title="An object that represents a set of data.">Set</a> is a plain JavaScript object used to represent a <a href="https://en.wikipedia.org/wiki/Set_theory#Basic_concepts_and_notation" title="set">set</a> of data usually sent to the server to fetch a list of records. For example, a list of all completed todos might be represented by:</p> <pre><code>{complete: true} </code></pre> <p>This set might be passed to <a href="can-connect/can/map/map.getList.html" title="Gets a list of instances of the map type.">getList</a> like:</p> <pre><code>Todo.getList({complete: true}) </code></pre> <p>An <a href="can-set.Algebra.html" title="Perform set logic with an awareness of how certain properties represent a set.">Algebra</a> is used to detail the behavior of these sets, often using already provided <a href="can-set.props.html" title="Contains a collection of prop generating functions. The following functions create compares objects that can be mixed together to create a set Algebra. var set = require("can-set"); var algebra = new set.Algebra( { // ignore this property in set algebra sessionId: function(){ return true } }, set.props.boolean("completed"), set.props.rangeInclusive("start","end") );">props</a> comparators:</p> <pre><code>var todoAlgebra = new set.Algebra( set.props.boolean("complete"), set.props.id("_id") ); </code></pre> <p>Using an algebra, all sorts of special behaviors can be performed. For example, if we already loaded the incomplete todos (<code>{complete: false}</code>) and wanted to load all todos (<code>{}</code>), we could use a set <a href="can-set.Algebra.prototype.difference.html" title="">difference</a> to figure out how to load only the data that hasn't been loaded.</p> <pre><code class="language-js">todoAlgebra.difference({}, {complete: false}) //-> {complete: true} </code></pre> <p>These algebra's are typically used internally by either <a href="can-connect.html" title="can-connect provides persisted data middleware. Use it to assemble powerful model layers for any JavaScript project.">can-connect</a> or <a href="can-fixture.html" title="can-fixture intercepts an AJAX request and simulates the response with a file or function.">can-fixture</a> to provide these special behaviors:</p> <pre><code class="language-js">var cacheConnection = connect([ require("can-connect/data/memory-cache/memory-cache") ],{ algebra: todoAlgebra }); var todoConnection = connect([ require("can-connect/data/url/url"), require("can-connect/cache-requests/cache-requests") ],{ cacheConnection: cacheConnection, url: "/todos", algebra: todoAlgebra }); </code></pre> <pre><code class="language-js">var todoStore = fixture.store([ { _id : 1, name : 'Do the dishes', complete: true }, { _id : 2, name : 'Walk the dog', complete: false } ], todoAlgebra ); fixture("/todos/{_id}", todoStore); </code></pre> <p>The best way to think about <code>can-set</code> is that its a way to detail the behavior of your service layer so other utilities can benefit.</p> <h2>Solving Common Issues</h2> <p>Configuring the proper <code>set.Algebra</code> can be tricky. The best way to make sure you have things working is to create an algebra and make sure some of the basics work.</p> <p>The most common problem is that your <code>algebra</code> isn't configured to know what instance data belongs in which set.</p> <p>For example, <code>{id: 1, name: "do dishes"}</code> should belong to the set <code>{sort: "name asc"}</code>, but it doesn't:</p> <pre><code class="language-js">var algebra = new set.Algebra(); algebra.has({sort: "name asc"}, {id: 1, name: "do dishes"}) //-> false </code></pre> <p>The fix is to either ignore <code>sort</code> like:</p> <pre><code class="language-js">var algebra = new set.Algebra({ sort: function() { return true; } }); algebra.has({sort: "name asc"}, {id: 1, name: "do dishes"}) //-> false </code></pre> <p>Or even better, make <code>sort</code> actually able to understand sorting:</p> <pre><code class="language-js">var algebra = new set.Algebra( set.props.sort("sort") ); algebra.has({sort: "name asc"}, {id: 1, name: "do dishes"}) //-> true </code></pre> <p>Similarly, you can verify that <a href="can-set.Algebra.prototype.getSubset.html" title="">getSubset</a> works. The following, with a default algebra gives the wrong results:</p> <pre><code class="language-js">var algebra = new set.Algebra(); algebra.getSubset( {offset: 1, limit: 2}, {}, [ {id: 1, name: "do dishes"} {id: 2, name: "mow lawn"}, {id: 3, name: "trash"}]) //-> [] </code></pre> <p>This is because it's looking for instance data where <code>offset===1</code> and <code>limit===2</code>. Again, you can teach your algebra what to do with these properties like:</p> <pre><code class="language-js">var algebra = new set.Algebra( set.props.offsetLimit("offset","limit") ); algebra.getSubset( {offset: 1, limit: 2}, {}, [ {id: 1, name: "do dishes"} {id: 2, name: "mow lawn"}, {id: 3, name: "trash"}]) //-> [ // {id: 2, name: "mow lawn"}, // {id: 3, name: "trash"} // ] </code></pre> </section> <script type="text/javascript"> var docObject = {"src":{"path":"node_modules/can-set/docs/can-set.md"},"description":" \ncan-set is a utility for comparing [can-set/Set sets] that are represented by the parameters commonly passed to service requests.\n\n","type":"module","title":"","types":[{"type":"Object","options":[],"description":"\n\nOnce you've imported the `can-set` module into your project, use it to create a `set.Algebra` and then use that to compare and perform operations on sets. \n\n```js\nvar set = require('can-set');\n// create an algebra\nvar algebra = new set.Algebra(\n // specify the unique identifier on data\n set.props.id(\"_id\"), \n // specify that completed can be true, false or undefined\n set.props.boolean(\"completed\"),\n // specify properties that define pagination\n set.props.rangeInclusive(\"start\",\"end\"),\n // specify the property that controls sorting\n set.props.sort(\"orderBy\"),\n)\n\n// compare two sets\nalgebra.subset({start: 2, end: 3}, {start: 1, end: 4}) //-> true\nalgebra.difference({} , {completed: true}) //-> {completed: false}\n\n// perform operations on sets\nalgebra.getSubset({start: 2,end: 3},{start: 1,end: 4},\n [{id: 1},{id: 2},{id: 3},{id: 4}])\n//-> [{id: 2},{id: 3}]\n```\n"}],"name":"can-set","parent":"can-core","package":{"_args":[[{"raw":"can-set@1.0.2","scope":null,"escapedName":"can-set","name":"can-set","rawSpec":"1.0.2","spec":"1.0.2","type":"version"},"/Users/kevin/dev/canjs"]],"_from":"can-set@1.0.2","_id":"can-set@1.0.2","_inCache":true,"_location":"/can-set","_nodeVersion":"5.10.1","_npmOperationalInternal":{"host":"packages-12-west.internal.npmjs.com","tmp":"tmp/can-set-1.0.2.tgz_1478805677332_0.1146602937951684"},"_npmUser":{"name":"justinbmeyer","email":"justin@bitovi.com"},"_npmVersion":"3.8.3","_phantomChildren":{},"_requested":{"raw":"can-set@1.0.2","scope":null,"escapedName":"can-set","name":"can-set","rawSpec":"1.0.2","spec":"1.0.2","type":"version"},"_requiredBy":["/","/can-connect","/can-fixture","/can-map-backup"],"_resolved":"https://registry.npmjs.org/can-set/-/can-set-1.0.2.tgz","_shasum":"54887ac58dea92f4ba0c5574c20a8b5755775418","_shrinkwrap":null,"_spec":"can-set@1.0.2","_where":"/Users/kevin/dev/canjs","author":{"name":"Bitovi"},"bit-docs":{"dependencies":{"bit-docs-glob-finder":"^0.0.5","bit-docs-dev":"^0.0.3","bit-docs-js":"^0.0.4","bit-docs-generate-readme":"^0.0.10"},"glob":{"pattern":"**/*.{js,md}","ignore":"node_modules/**/*"},"parent":"can-set","readme":{"apis":"./docs/apis.json"}},"bugs":{"url":"https://github.com/canjs/can-set/issues"},"dependencies":{"can-util":"^3.0.1"},"description":"Set logic for CanJS","devDependencies":{"bit-docs":"^0.0.7","jshint":"^2.7.0","steal":"^0.15.3","steal-qunit":"0.1.1","steal-tools":"^0.15.7","testee":"^0.2.0"},"directories":{},"dist":{"shasum":"54887ac58dea92f4ba0c5574c20a8b5755775418","tarball":"https://registry.npmjs.org/can-set/-/can-set-1.0.2.tgz"},"gitHead":"6063157ab45961450cc6b96fc25e00c168b69a63","homepage":"https://github.com/canjs/can-set","keywords":["canjs"],"license":"MIT","main":"src/set.js","maintainers":[{"name":"daffl","email":"daff@neyeon.de"},{"name":"garrettreed","email":"garrett@garrettreed.co"},{"name":"justinbmeyer","email":"justin@bitovi.com"},{"name":"matthewp","email":"matthew@matthewphillips.info"},{"name":"phillipskevin","email":"kphillips86@gmail.com"},{"name":"sinjhin","email":"john@ardea.io"}],"name":"can-set","optionalDependencies":{},"readme":"ERROR: No README data found!","repository":{"type":"git","url":"git+https://github.com/canjs/can-set.git"},"scripts":{"build":"node build.js","jshint":"jshint src/. --config","postversion":"git push --tags && git checkout master && git branch -D release && git push","preversion":"npm test && npm run build","release:major":"npm version major && npm publish","release:minor":"npm version minor && npm publish","release:patch":"npm version patch && npm publish","release:pre":"npm version prerelease && npm publish","test":"npm run jshint && npm run testee","testee":"testee test/test.html --browsers firefox","version":"git commit -am \"Update dist for release\" && git checkout -b release && git add -f dist/"},"system":{"npmIgnore":["testee"]},"version":"1.0.2"},"comment":" ","pathToRoot":".."}; </script> </article> <footer><p>CanJS is part of <a href="http://donejs.com" target="_blank">DoneJS</a>. 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