pip-services3-commons-nodex/src/reflect/RecursiveObjectWriter.ts

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

/** @module reflect */
import { IntegerConverter } from '../convert/IntegerConverter';
import { ObjectReader } from './ObjectReader';
import { ObjectWriter } from './ObjectWriter';
import { RecursiveObjectReader } from './RecursiveObjectReader';

/**
 * Helper class to perform property introspection and dynamic writing.
 * 
 * It is similar to [[ObjectWriter]] but writes properties recursively
 * through the entire object graph. Nested property names are defined
 * using dot notation as "object.subobject.property"
 *
 * @see [[PropertyReflector]]
 * @see [[ObjectWriter]]
 */
export class RecursiveObjectWriter {

	private static createProperty(obj: any, names: string[], nameIndex: number): any {
		// If next field is index then create an array
		let subField = names.length > nameIndex + 1 ? names[nameIndex + 1] : null;
		let subFieldIndex = IntegerConverter.toNullableInteger(subField);
		if (subFieldIndex != null) {
			return [];
		}

		// Else create a dictionary
		return {};
	}
	
    private static performSetProperty(obj: any, names: string[], nameIndex: number, value: any): any {
		if (nameIndex < names.length - 1) {
			let subObj = ObjectReader.getProperty(obj, names[nameIndex]);
			if (subObj != null) {
				RecursiveObjectWriter.performSetProperty(subObj, names, nameIndex + 1, value);
			} else {
				subObj = RecursiveObjectWriter.createProperty(obj, names, nameIndex);
				if (subObj != null) {					
					RecursiveObjectWriter.performSetProperty(subObj, names, nameIndex + 1, value);
					ObjectWriter.setProperty(obj, names[nameIndex], subObj);
				}
			}
		} else {
			ObjectWriter.setProperty(obj, names[nameIndex], value);
		}
	}

	/**
	 * Recursively sets value of object and its subobjects 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.
	 * 
	 * If the property does not exist or introspection fails
	 * this method doesn't do anything and doesn't any throw errors.
	 * 
	 * @param obj 	an object to write property to.
	 * @param name 	a name of the property to set.
	 * @param value a new value for the property to set.
	 */ 
	public static setProperty(obj: any, name: string, value: any): void {
        if (obj == null || name == null) return;

        let names = name.split(".");
        if (names == null || names.length == 0) {
        	return;
		}

        RecursiveObjectWriter.performSetProperty(obj, names, 0, value);
	}

	/**
	 * Recursively sets values of some (all) object and its subobjects properties.
	 * 
     * The object can be a user defined object, map or array.
     * Property values correspondently are object properties,
     * map key-pairs or array elements with their indexes.
	 * 
	 * If some properties do not exist or introspection fails
	 * they are just silently skipped and no errors thrown.
	 * 
	 * @param obj 		 an object to write properties to.
	 * @param values 	a map, containing property names and their values.
	 * 
	 * @see [[setProperty]]
	 */
	public static setProperties(obj: any, values: any): void {
		if (values == null) return;
		
		for (let key in values) {
            let value = values[key];
			RecursiveObjectWriter.setProperty(obj, key, value);
		}
	}

	/**
	 * Copies content of one object to another object
	 * by recursively reading all properties from source object
	 * and then recursively writing them to destination object.
	 * 
	 * @param dest 	a destination object to write properties to.
	 * @param src 	a source object to read properties from
	 */
	public static copyProperties(dest: any, src: any): void {
		if (dest == null || src == null) return;
		
		let values = RecursiveObjectReader.getProperties(src);
		RecursiveObjectWriter.setProperties(dest, values);
	}

}