Expression

This plugin assists with exposing custom expressions to Player content.

Usage

Core

Define handlers for the expressions you wish to add:

import {
  ExpressionHandler,
  ExpressionContext,
} from "@player-ui/expression-plugin";

const customExpressionHandler: ExpressionHandler = (ctx: ExpressionContext) => {
  return "Hello World!";
};

Register with Player. Subsequent registrations of an expression with the same name will override previous values.

import { Player } from "@player-ui/player";
import { ExpressionPlugin } from "@player-ui/expression-plugin";

const player = new Player({
  plugins: [
    new ExpressionPlugin([["myCustomFunction", customExpressionHandler]]),
  ],
});

Any calls to myCustomFunction() within the flow will utilize the newly registered expression:

{
  "asset": {
    "id": "sample",
    "type": "text",
    "value": "@[ myCustomFunction() ]@"
  }
}

Android

The ExpressionPlugin enables consumers to register custom expressions in native JVM code. Simply supply a map of expression name to handler on instantiation, and the expressions will be available within the content. Handlers receive arguments are as a List<Any?> and are permitted to return Any?.

Usage

In build.gradle

implementation "com.intuit.playerui.plugins:expression:$PLAYER_VERSION"

In Player constructor

import com.intuit.playerui.plugins.expression.ExpressionPlugin

val expressionPlugin = ExpressionPlugin(
     "hello" to { args: List<Any?> ->
        when (val name = args.firstOfNull()) {
            null -> "goodbye"
            else -> "hello $name"
        }
    }
)
AndroidPlayer(expressionPlugin)

In Player content

{
  "id": "hello-world-text",
  "type": "text",
  "value": "@[hello('world')]@"
}

iOS

CocoaPods

Add the subspec to your Podfile

pod 'PlayerUI/ExpressionPlugin'

Swift Usage

The ExpressionPlugin lets you register custom expressions to run native code:

{
  "id": "textAsset",
  "type": "text",
  "value": "@[ myExpression() ]@"
}

let expressionPlugin = ExpressionPlugin(expressions: [
  "myExpression": { _ in
      return "Some Value"
  }
])

Arguments

Arguments can be passed to custom expressions, and your handler receives the arguments as an array of Any:

{
  "id": "textAsset",
  "type": "text",
  "value": "@[ myExpression('world') ]@"
}

let expressionPlugin = ExpressionPlugin(expressions: [
  "myExpression": { (args: [Any]) -> Any? in
      guard let string = args.first as? String else { return nil }
      return "Hello " + string
  }
])