@microsoft.azure/autorest.incubator/dist/common/intersect.js

AutoRest incubator project

"use strict";
Object.defineProperty(exports, "__esModule", { value: true });
/**
 * Creates an intersection object from two source objects.
 *
 * Typescript nicely supports defining intersection types (ie, Foo & Bar )
 * But if you have two seperate *instances*, and you want to use them as the implementation
 * of that intersection, the language doesn't solve that for you.
 *
 * This function creates a strongly typed proxy type around the two objects,
 * and returns members for the intersection of them.
 *
 * This works well for properties and member functions the same.
 *
 * Members in the primary object will take precedence over members in the secondary object if names conflict.
 *
 * This can also be used to "add" arbitrary members to an existing type (without mutating the original object)
 *
 * @example
 * const combined = intersect( new Foo(), { test: () => { console.log('testing'); } });
 * combined.test(); // writes out 'testing' to console
 *
 * @param primary primary object - members from this will have precedence.
 * @param secondary secondary object - members from this will be used if primary does not have a member
 */
function intersect(primary, secondary) {
    return new Proxy({ primary, secondary }, {
        // member get proxy handler 
        get(target, property, receiver) {
            // check for properties on the objects first
            const propertyName = property.toString();
            if (Object.getOwnPropertyNames(target.primary).indexOf(propertyName) > -1) {
                return target.primary[property];
            }
            if (Object.getOwnPropertyNames(target.secondary).indexOf(propertyName) > -1) {
                return target.secondary[property];
            }
            // try binding member function
            if (typeof (target.primary[property]) === 'function') {
                return target.primary[property].bind(primary);
            }
            if (typeof (target.secondary[property]) === 'function') {
                return target.secondary[property].bind(secondary);
            }
            return target.primary[property] || target.secondary[property];
        },
        // member set proxy handler 
        set(target, property, value) {
            const propertyName = property.toString();
            if (Object.getOwnPropertyNames(target.primary).indexOf(propertyName) > -1) {
                return target.primary[property] = value;
            }
            if (Object.getOwnPropertyNames(target.secondary).indexOf(propertyName) > -1) {
                return target.secondary[property] = value;
            }
            return undefined;
        }
    });
}
exports.intersect = intersect;
//# sourceMappingURL=intersect.js.map