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BSR UI-KIT Relaunch

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# json-logic-js This parser accepts [JsonLogic](http://jsonlogic.com) rules and executes them in JavaScript. The JsonLogic format is designed to allow you to share rules (logic) between front-end and back-end code (regardless of language difference), even to store logic along with a record in a database. JsonLogic is documented extensively at [JsonLogic.com](http://jsonlogic.com), including examples of every [supported operation](http://jsonlogic.com/operations.html) and a place to [try out rules in your browser](http://jsonlogic.com/play.html). The same format can also be executed in PHP by the library [json-logic-php](https://github.com/jwadhams/json-logic-php/) ## Installation We recommend that you install this library with a package manager, like [NPM](https://www.npmjs.com/) (or Yarn, etc): ```bash npm install json-logic-js ``` Note that this project uses a [module loader](http://ricostacruz.com/cheatsheets/umdjs.html) that also makes it suitable for RequireJS projects. If that doesn't suit you, and you want to manage updates yourself, the entire library is self-contained in `logic.js` and you can download it straight into your project as you see fit. ```bash curl -O https://raw.githubusercontent.com/jwadhams/json-logic-js/master/logic.js ``` ## Examples ### Simple ```js jsonLogic.apply( { "==" : [1, 1] } ); // true ``` This is a simple test, equivalent to `1 == 1`. A few things about the format: 1. The operator is always in the "key" position. There is only one key per JsonLogic rule. 1. The values are typically an array. 1. Each value can be a string, number, boolean, array (non-associative), or null ### Compound Here we're beginning to nest rules. ```js jsonLogic.apply( {"and" : [ { ">" : [3,1] }, { "<" : [1,3] } ] } ); // true ``` In an infix language (like JavaScript) this could be written as: ```js ( (3 > 1) && (1 < 3) ) ``` ### Data-Driven Obviously these rules aren't very interesting if they can only take static literal data. Typically `jsonLogic` will be called with a rule object and a data object. You can use the `var` operator to get attributes of the data object: ```js jsonLogic.apply( { "var" : ["a"] }, // Rule { a : 1, b : 2 } // Data ); // 1 ``` If you like, we support [syntactic sugar](https://en.wikipedia.org/wiki/Syntactic_sugar) on unary operators to skip the array around values: ```js jsonLogic.apply( { "var" : "a" }, { a : 1, b : 2 } ); // 1 ``` You can also use the `var` operator to access an array by numeric index: ```js jsonLogic.apply( {"var" : 1 }, [ "apple", "banana", "carrot" ] ); // "banana" ``` Here's a complex rule that mixes literals and data. The pie isn't ready to eat unless it's cooler than 110 degrees, *and* filled with apples. ```js var rules = { "and" : [ {"<" : [ { "var" : "temp" }, 110 ]}, {"==" : [ { "var" : "pie.filling" }, "apple" ] } ] }; var data = { "temp" : 100, "pie" : { "filling" : "apple" } }; jsonLogic.apply(rules, data); // true ``` ### Always and Never Sometimes the rule you want to process is "Always" or "Never." If the first parameter passed to `jsonLogic` is a non-object, non-associative-array, it is returned immediately. ```js //Always jsonLogic.apply(true, data_will_be_ignored); // true //Never jsonLogic.apply(false, i_wasnt_even_supposed_to_be_here); // false ``` ## Compatibility This library makes use of `Array.map` and `Array.reduce`, so it's not *exactly* Internet Explorer 8 friendly. If you want to use JsonLogic *and* support deprecated browsers, you could easily use [BabelJS's polyfill](https://babeljs.io/docs/usage/polyfill/) or directly incorporate the polyfills documented on MDN for [map](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/map) and [reduce](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/reduce). ## Customization It's not possible to include everyone's excellent ideas without the core library bloating, bringing in a ton of outside dependencies, or occasionally causing use case conflicts (some people need to safely execute untrusted rules, some people need to change outside state). Check out the [documentation for adding custom operations](http://jsonlogic.com/add_operation.html) and be sure to stop by the [Wiki page of custom operations](https://github.com/jwadhams/json-logic-js/wiki/Custom-Operations) to see if someone has already solved your problem or to share your solution.