pip-services3-commons-nodex/obj/src/reflect/ObjectReader.js

Portable abstractions and patterns for Pip.Services in Node.js / ES2017

"use strict";
Object.defineProperty(exports, "__esModule", { value: true });
exports.ObjectReader = void 0;
/** @module reflect */
const PropertyReflector_1 = require("./PropertyReflector");
const IntegerConverter_1 = require("../convert/IntegerConverter");
/**
 * Helper class to perform property introspection and dynamic reading.
 *
 * In contrast to [[PropertyReflector]] which only introspects regular objects,
 * this ObjectReader is also able to handle maps and arrays.
 * For maps properties are key-pairs identified by string keys,
 * For arrays properties are elements identified by integer index.
 *
 * This class has symmetric implementation across all languages supported
 * by Pip.Services toolkit and used to support dynamic data processing.
 *
 * Because all languages have different casing and case sensitivity rules,
 * this ObjectReader treats all property names as case insensitive.
 *
 * @see [[PropertyReflector]]
 *
 * ### Example ###
 *
 *     let myObj = new MyObject();
 *
 *     let properties = ObjectReader.getPropertyNames();
 *     ObjectReader.hasProperty(myObj, "myProperty");
 *     let value = PropertyReflector.getProperty(myObj, "myProperty");
 *
 *     let myMap = { key1: 123, key2: "ABC" };
 *     ObjectReader.hasProperty(myMap, "key1");
 *     let value = ObjectReader.getProperty(myMap, "key1");
 *
 *     let myArray = [1, 2, 3]
 *     ObjectReader.hasProperty(myArrat, "0");
 *     let value = ObjectReader.getProperty(myArray, "0");
 */
class ObjectReader {
    /**
     * Gets a real object value.
     * If object is a wrapper, it unwraps the value behind it.
     * Otherwise it returns the same object value.
     *
     * @param obj   an object to unwrap..
     * @returns an actual (unwrapped) object value.
     */
    static getValue(obj) {
        // Todo: just a blank implementation for compatibility
        return obj;
    }
    /**
     * Checks if object has a property with specified name.
     *
     * The object can be a user defined object, map or array.
     * The property name correspondently must be object property,
     * map key or array index.
     *
     * @param obj 	an object to introspect.
     * @param name 	a name of the property to check.
     * @returns true if the object has the property and false if it doesn't.
     */
    static hasProperty(obj, name) {
        if (obj == null || name == null) {
            return false;
        }
        else if (typeof obj === "object" && !(obj instanceof Date)) {
            return PropertyReflector_1.PropertyReflector.hasProperty(obj, name);
        }
        else if (Array.isArray(obj)) {
            let index = IntegerConverter_1.IntegerConverter.toNullableInteger(name);
            return index != null && index < obj.length;
        }
        else {
            return false;
        }
    }
    /**
     * Gets value of object property specified by its name.
     *
     * The object can be a user defined object, map or array.
     * The property name correspondently must be object property,
     * map key or array index.
     *
     * @param obj 	an object to read property from.
     * @param name 	a name of the property to get.
     * @returns the property value or null if property doesn't exist or introspection failed.
     */
    static getProperty(obj, name) {
        if (obj == null || name == null) {
            return null;
        }
        else if (typeof obj === "object" && !(obj instanceof Date)) {
            return PropertyReflector_1.PropertyReflector.getProperty(obj, name);
        }
        else if (Array.isArray(obj)) {
            let index = IntegerConverter_1.IntegerConverter.toNullableInteger(name);
            return index != null && index < obj.length ? obj[index] : null;
        }
        else {
            return null;
        }
    }
    /**
     * Gets names of all properties implemented in specified object.
     *
     * The object can be a user defined object, map or array.
     * Returned property name correspondently are object properties,
     * map keys or array indexes.
     *
     * @param obj   an objec to introspect.
     * @returns a list with property names.
     */
    static getPropertyNames(obj) {
        let properties = [];
        if (obj == null) {
            // Do nothing
        }
        else if (typeof obj === "object" && !(obj instanceof Date)) {
            properties = PropertyReflector_1.PropertyReflector.getPropertyNames(obj);
        }
        else if (Array.isArray(obj)) {
            let length = obj.length;
            for (let index = 0; index < length; index++) {
                properties.push(index.toString());
            }
        }
        else {
            // Do nothing
        }
        return properties;
    }
    /**
     * Get values of all properties in specified object
     * and returns them as a map.
     *
     * The object can be a user defined object, map or array.
     * Returned properties correspondently are object properties,
     * map key-pairs or array elements with their indexes.
     *
     * @param obj   an object to get properties from.
     * @returns a map, containing the names of the object's properties and their values.
     */
    static getProperties(obj) {
        let map = {};
        if (obj == null) {
            // Do nothing
        }
        else if (typeof obj === "object" && !(obj instanceof Date)) {
            map = PropertyReflector_1.PropertyReflector.getProperties(obj);
        }
        else if (Array.isArray(obj)) {
            let length = obj.length;
            for (let index = 0; index < length; index++) {
                map[index.toString()] = obj[index];
            }
        }
        else {
            // Do nothing
        }
        return map;
    }
}
exports.ObjectReader = ObjectReader;
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