botbuilder-dialogs-adaptive/src/jsonExtensions.ts

Rule system for the Microsoft BotBuilder dialog system.

/**
 * Copyright (c) Microsoft Corporation. All rights reserved.
 * Licensed under the MIT License.
 */
/**
 * @module botbuilder-dialogs-adaptive
 */

import { DialogStateManager } from 'botbuilder-dialogs';
import { ValueExpression } from 'adaptive-expressions';

/**
 * Replaces the binding paths in a JSON value with the evaluated results recursively.
 *
 * @param state A scope for looking up variables.
 * @param unit An object.
 * @returns Deep data binding result.
 */
export function replaceJsonRecursively(state: DialogStateManager, unit: object): any {
    if (typeof unit === 'string') {
        const { value, error } = new ValueExpression(unit).tryGetValue(state);
        if (!error) {
            return value;
        }
        return unit;
    }

    if (Array.isArray(unit)) {
        const result = [];
        for (const child of unit) {
            result.push(replaceJsonRecursively(state, child));
        }
        return result;
    }

    if (typeof unit === 'object') {
        const result = {};
        for (const key in unit) {
            result[key] = replaceJsonRecursively(state, unit[key]);
        }
        return result;
    }

    return unit;
}

/**
 * Evaluate ValueExpression according the value type.
 *
 * @param state Input ValueExpression
 * @param valExpr A scope for looking up variables.
 * @returns Deep data binding result.
 */
export function evaluateExpression(state: DialogStateManager, valExpr: ValueExpression): any {
    return valExpr.expressionText == null ? replaceJsonRecursively(state, valExpr.value) : valExpr.getValue(state);
}