diffusion/src/node_modules/events/stream.js

Diffusion JavaScript client

/*eslint valid-jsdoc: "off"*/
var _implements = require('util/interface')._implements;

var Stream = require('../../events/stream');

/**
 * Set one or more properties on an object;
 * 
 * @param {Object} object - The object to attach properties to
 * @param {String|Object} key - The key, or an object map of properties
 * @param {*} value - If the key is a string, this is the value to be associated with it
 * 
 * @returns The object, with attached properties 
 */
function attach(object, key, value, allowedEvents) {
    if (typeof key === 'object') {
        for (var k in key) {
            attach(object, k, key[k], allowedEvents);
        }
    } else if (value) {
        if (object[key] === undefined) {
            if (allowedEvents && allowedEvents.indexOf(key) === -1) {
                throw new Error('Event ' + key + ' not emitted on this stream, allowed events are ' + allowedEvents);
            }
            object[key] = [];
        } 

        object[key].push(value);
    }
    
    return object;
}

/**
 * Remove one or more properties from an object
 * 
 * @param {Object} object - The object to remove properties from
 * @param {String|Object} key - The key, or an object map of properties
 * @param {*} value - If the key is a string, this is the value to remove from it
 * 
 * @returns The object, sans specified properties 
 */
function remove(object, key, value) {
    if (typeof key === 'object') {
        for (var k in key) {
            remove(object, k, key[k]);
        }
    } else if (object[key]) {
        if (value) {
            object[key] = object[key].filter(function(e) {
                return e !== value;
            });
        } else {
            object[key] = [];
        }
    }

    return object;
}

function StreamImpl(listeners, error, close, events) {
    var allowedEvents;

    if (events) {
        allowedEvents = ['close', 'error', 'complete'].concat(events);
    }

    this.on = function(event, fn) {
        attach(listeners, event, fn, allowedEvents);
        return this;
    };
    
    this.off = function(event, fn) {
        remove(listeners, event, fn);
        return this;
    };
    
    this.close = function(reason) {
        close(reason);
        return this;
    };
    
    this.error = function(reason) {
        error(reason);
        return this;
    };
}

module.exports = _implements(Stream, StreamImpl);