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v4.1.0
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Converted internal Gawk state from a class to a plain object to allow multiple gawk instances to play nice together. Also added a version to the gawk state just in case.
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@cb1kenobi
cb1kenobi committed Apr 8, 2017
1 parent 0bfadd5 commit 46f9f32
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Showing 3 changed files with 123 additions and 119 deletions.
2 changes: 1 addition & 1 deletion package.json
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Original file line number Diff line number Diff line change
@@ -1,6 +1,6 @@
{
"name": "gawk",
"version": "4.0.2",
"version": "4.1.0",
"description": "Observable JavaScript object model",
"main": "./dist/index.js",
"author": "Chris Barber <[email protected]> (https://github.com/cb1kenobi)",
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237 changes: 119 additions & 118 deletions src/index.js
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Original file line number Diff line number Diff line change
Expand Up @@ -2,121 +2,9 @@ if (!Error.prepareStackTrace) {
require('source-map-support/register');
}

export class Gawk {
/**
* A list of all the gawk object's parents. These parents are notified when a change occurs.
* @type {Set}
*/
parents = new Set;

/**
* A map of listener functions to call invoke when a change occurs. The associated key value is
* the optional filter to apply to the listener.
* @type {Map}
*/
listeners = new Map;

/**
* A map of listener functions to the last known hash of the stringified value. This is used to
* detect if a filtered watch should be notified.
* @type {WeakMap}
*/
previous = new WeakMap;

/**
* A list of child objects that are modified while paused.
* @type {Set}
*/
queue = null;
import fs from 'fs';

/**
* Creates the internal Gawk state.
*
* @param {Object} instance - The object being gawked.
*/
constructor(instance) {
this.instance = instance;
}

/**
* Dispatches change notifications to the listeners.
*/
pause() {
if (!this.queue) {
this.queue = new Set;
}
}

/**
* Unpauses the gawk notifications and sends out any pending notifications.
*/
resume() {
if (this.queue) {
const queue = this.queue;
this.queue = null;
for (const instance of queue) {
this.notify(instance);
}
}
}

/**
* Dispatches change notifications to the listeners.
*
* @param {Object|Array} [source] - The gawk object that was modified.
*/
notify(source) {
if (source === undefined) {
source = this.instance;
}

if (this.queue) {
this.queue.add(this.instance);
return;
}

// notify all of this object's listeners
for (const [ listener, filter ] of this.listeners) {
if (filter) {
let obj = this.instance;
let found = true;

// find the value we're interested in
for (let i = 0, len = filter.length; obj && typeof obj === 'object' && i < len; i++) {
if (!obj.hasOwnProperty(filter[i])) {
found = false;
obj = undefined;
break;
}
obj = obj[filter[i]];
}

// compute the hash of the stringified value
const str = JSON.stringify(obj) || '';
let hash = 5381;
let i = str.length;
while (i) {
hash = (hash * 33) ^ str.charCodeAt(--i);
}
hash = hash >>> 0;

// check if the value changed
if ((found || this.previous.has(listener)) && hash !== this.previous.get(listener)) {
listener(obj, source);
}

this.previous.set(listener, hash);
} else {
listener(this.instance, source);
}
}

// notify all of this object's parents
for (const parent of this.parents) {
parent.__gawk__.notify(source);
}
}
}
const version = JSON.parse(fs.readFileSync(`${__dirname}/../package.json`, 'utf-8')).version;

/**
* Determines if the specified variable is gawked.
Expand All @@ -125,7 +13,7 @@ export class Gawk {
* @returns {Boolean}
*/
export function isGawked(it) {
return it && typeof it === 'object' && it.__gawk__ instanceof Gawk;
return !!(it && typeof it === 'object' && it.__gawk__ && typeof it.__gawk__ === 'object');
}

/**
Expand All @@ -136,7 +24,7 @@ export function isGawked(it) {
* @returns {Array|Object|*}
*/
export default function gawk(value, parent) {
if (parent !== undefined && (typeof parent !== 'object' || !(parent.__gawk__ instanceof Gawk))) {
if (parent !== undefined && !isGawked(parent)) {
throw new TypeError('Expected parent to be gawked');
}

Expand All @@ -147,7 +35,7 @@ export default function gawk(value, parent) {

let gawked;

if (value.__gawk__ instanceof Gawk) {
if (typeof value.__gawk__ === 'object') {
// already gawked
if (value === parent) {
throw new Error('The parent must not be the same object as the value');
Expand Down Expand Up @@ -210,7 +98,120 @@ export default function gawk(value, parent) {
});

Object.defineProperty(gawked, '__gawk__', {
value: new Gawk(gawked)
value: {
/**
* A map of listener functions to call invoke when a change occurs. The associated
* key value is the optional filter to apply to the listener.
* @type {Map}
*/
listeners: new Map,

/**
* A list of all the gawk object's parents. These parents are notified when a change
* occurs.
* @type {Set}
*/
parents: new Set,

/**
* A map of listener functions to the last known hash of the stringified value. This
* is used to detect if a filtered watch should be notified.
* @type {WeakMap}
*/
previous: new WeakMap,

/**
* A list of child objects that are modified while paused.
* @type {Set}
*/
queue: null,

/**
* The Gawk version. This is helpful for identifying the revision of this internal
* structure.
* @type {String}
*/
version,

/**
* Dispatches change notifications to the listeners.
*
* @param {Object|Array} [source] - The gawk object that was modified.
*/
notify: function notify(source) {
if (source === undefined) {
source = gawked;
}

if (this.queue) {
this.queue.add(gawked);
return;
}

// notify all of this object's listeners
for (const [ listener, filter ] of this.listeners) {
if (filter) {
let obj = gawked;
let found = true;

// find the value we're interested in
for (let i = 0, len = filter.length; obj && typeof obj === 'object' && i < len; i++) {
if (!obj.hasOwnProperty(filter[i])) {
found = false;
obj = undefined;
break;
}
obj = obj[filter[i]];
}

// compute the hash of the stringified value
const str = JSON.stringify(obj) || '';
let hash = 5381;
let i = str.length;
while (i) {
hash = (hash * 33) ^ str.charCodeAt(--i);
}
hash = hash >>> 0;

// check if the value changed
if ((found || this.previous.has(listener)) && hash !== this.previous.get(listener)) {
listener(obj, source);
}

this.previous.set(listener, hash);
} else {
listener(gawked, source);
}
}

// notify all of this object's parents
for (const parent of this.parents) {
parent.__gawk__.notify(source);
}
},

/**
* Dispatches change notifications to the listeners.
*/
pause: function pause() {
if (!this.queue) {
this.queue = new Set;
}
},

/**
* Unpauses the gawk notifications and sends out any pending notifications.
*/
resume: function resume() {
if (this.queue) {
const queue = this.queue;
this.queue = null;
for (const instance of queue) {
this.notify(instance);
}
}
}
}
});

// gawk any object properties
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3 changes: 3 additions & 0 deletions test/test-object.js
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Original file line number Diff line number Diff line change
Expand Up @@ -2,12 +2,15 @@ import gawk, { Gawk, isGawked } from '../src/index';

import { EventEmitter } from 'events';

const version = require('./../package.json').version;

describe('gawk() object', () => {
it('should gawk empty object', () => {
const obj = {};
const gobj = gawk(obj);
expect(isGawked(gobj)).to.be.true;
expect(gobj).to.deep.equal(obj);
expect(gobj.__gawk__.version).to.equal(version);
});

it('should passhthrough non-object values', () => {
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