When writing multi-line expressions, we recommend you place it in a separate script tag outside the JavaScript portion of the app, and set the type to text/plain with a unique ID you can use to reference the script in the appropriate place within JavaScript. renderer.valueExpression = "Round( ($feature.AGE_18UP / $feature.TOTAL_POP) * 100 )" When writing single-line expressions, you can simply wrap it in double or single quotes. You may use Arcade to write simple single-line expressions, or more complex multi-line epxressions. Within JavaScript apps, Arcade expressions are always referenced as a string value. ($feature.DEM_VOTES / $feature.TURNOUT ) * 100Īrcade is only executed within the context, or profile, in which it is understood. calculates the % of voters who voted for a This makes it easy to perform simple calculations using field values at runtime. Field values are referenced using the following syntax: $feature.fieldName Each field value is also considered a global variable. The $feature global variable allows you to access field values for features in a FeatureLayer. Global variables contain external values that are passed to a script during its execution – based on the execution profile. The power of Arcade is manifest in gaining access to global variables. You also have access to a playground that provides an environment for testing custom scripts based on your data. Read the full Arcade documentation including guides and the function reference for more details on how to write an Arcade expression. ![]() However, there are key differences between the two languages. In many respects Arcade's syntax is similar to JavaScript, allowing you to declare variables, perform logical operations, take advantage of built-in functions, and write custom functions. ![]() In future releases, other geometry functions may be added allowing you to calculate areas and lengths, and perform simple overlay operations in more complex expressions. In the initial release of Arcade, geometries can be created and referenced. What makes Arcade particularly unique to other expression and scripting languages is its inclusion of geometry functions. It was designed specifically for creating custom visualizations and labeling expressions with ArcGIS, allowing users to write, share, and execute custom expressions in ArcGIS Pro, ArcGIS Online, the ArcGIS Runtime APIs, and the ArcGIS API for JavaScript. Like other expression languages, it can perform mathematical calculations and evaluate logical statements. Arcade is a lightweight and secure expression language written for use with ArcGIS.
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