I was looking at the sample code for the tutorial at https://forge.autodesk.com/blog/custom-window-selection-forge-viewer-part-iii which is located at https://github.com/Autodesk-Forge/forge-rcdb.nodejs/blob/master/src/client/viewer.components/Viewer.Extensions.Dynamic/Viewing.Extension.SelectionWindow/Viewing.Extension.SelectionWindow.Tool.js as well as the documentation at https://developer.autodesk.com/en/docs/viewer/v2/reference/javascript/toolinterface/ --- Most of these functions are getting called properly in my tool such as handleSingleClick, handleMouseMove, handleKeyDown, and so on, but two of them are not getting hit -- handleButtonDown and handleButtonUp. I was using viewer version 3.3.x but I have updated to use 4.0.x thinking that that might help to resolve the problem, but the same issue occurs in both versions. Thanks for any help.
The following code block from theAutodesk.Viewing.ToolController#__invokeStack(), _toolStack stands for activated tools in the ToolController, the method stands for callback functions started with handle, i.e. handleSingleClick, handleMouseMove, handleKeyDown, handleButtonDown, handleButtonUp, etc.
for( var n = _toolStack.length; --n >= 0; )
{
var tool = _toolStack[n];
if( tool[method] && tool[method](arg1, arg2) )
{
return true;
}
}
Based on my experience, if there is a handle function such as handleButtonDown or handleButtonUp executed before your custom tools' and returned true, then your handles will never be called.
Fortunately, Forge Viewer (v3.2) starts invoking a priority mechanism for custom tools registered in ToolController. ToolController will use the priority number to sort the tools in it, and the priority number of each tool is 0 by default. You can override the priority to make your tools be hit before other tools like this way, to add a function getPriority() to return a number greater than 0:
this.getPriority = function() {
return 100;
};
I found out that when using ES6 and the class syntax, extending your tool from Autodesk.Viewing.ToolInterface will prevent the overrides to work properly, probably because it is not implemented using prototype in the viewer source code.
You can simply create a class and implement the methods that are of interest for your tool:
// KO: not working!
class MyTool extends Autodesk.Viewing.ToolInterface {
getName () {
return 'MyTool'
}
getNames () {
return ['MyTool']
}
handleButtonDown (event, button) {
return false
}
}
// OK
class MyTool {
getName () {
return 'MyTool'
}
getNames () {
return ['MyTool']
}
handleButtonDown (event, button) {
return false
}
}
I am changing my es5 code to es6 in my Angular 1.6 file(s) so started using let and const instead of var but quite confused about named function expression whether it should be const or let ?
es5
var foo = function () { ... }
es6
let foo = () => { ... }
or
const foo = () => { ... }
does mixing let and const within same js file for named function does impact the performance or we should stick with var?
In my understanding, functions are the things that always unchangeable in one JS file so we can use const.
Please give some useful explanation.
The rules for const vs. let are the same whether you are assigning a function or any other value. If you don't intend or want to change the value (nearly always the case for functions), use const. However, notice that there are differences in hoisting behavior, although it is unlikely that would affect you.
Any performance difference will be negligible.
---Background---
I'm trying to learn current best data management practices and as far as I can tell that means stateless / stateful components and immutable data structure. I'm having problems with implementing latter (immutables). I'm trying to incorporate it into angular 2 without redux. Redux is on my list of things to learn but for now I want to use immutable.js without redux.
---The problem---
How do I create a copy of an array in a service and return it on demand? I have this example code (just for illustration purposes, I haven't tested it!):
import { Product } from './product';
import { Immutable } from './immutable';
export class ProductListService {
let id = 0;
const cheese = new Product(id++, 'cheese');
const ham = new Product(id++, 'ham');
const milk = new Product(id++, 'milk');
// I fill the list with some sample data
let oldProductList = Immutable.List.of(cheese, ham, milk);
let newProductList = [];
let returnProductList = oldProductList;
getProductList() {
return returnProductList;
}
addProduct() {
// As far as I know, this creates a deep immutable copy
newProductList = oldProductList.withMutations(function (list) {
list.push(new Product(id++, 'name'););
});
returnProductList = newProductList;
oldProductList = newProductList;
}
}
The above code is based on the example from the official docs where they just add a number to the variable each time they create a copy (I understand that is only for example purposes?). How do I go about creating new lists without using numbers? Do I use oldList / newList? Do I dynamically create new numbers for new variables so that I have a history of objects?
I feel I'm doing something wrong on a architectural level here. What is the correct approach? All immutable.js examples are using redux or show no real-life example, does someone know of a good material to learn about immutalbe.js (+ possible ng2?)
Thanks
Not sure i fully understand what you want to do here,
but consider this:if you just want to push one element to the list you should not use withMutations.
let list1 = Immutable.List(['one'])
let list2 = list1.push('two')
console.log(list1.toJS()) // ['one']
console.log(list2.toJS()) // ['one', 'two']
Applying a mutation to create a new immutable object results in some overhead, which can add up to a minor performance penalty. use withMutations only If you need to apply a series of mutations locally before returning
let list1 = Immutable.List(['one'])
var list2 = list1.withMutations(function (list) {
list.push('two').push('three').push('four').push('five');
});
console.log(list1.toJS()) //["one"]
console.log(list2.toJS()) //["one", "two", "three", "four", "five"]
here we create a temporary mutable (transient) copy of list 1 and apply a batch of mutations in a performant manner by using withMutations
I hope that answers your question
I have a JSON file which I need to iterate over, as shown below...
{
"device_id": "8020",
"data": [{
"Timestamp": "04-29-11 05:22:39 pm",
"Start_Value": 0.02,
"Abstract": 18.60,
"Editor": 65.20
}, {
"Timestamp": "04-29-11 04:22:39 pm",
"End_Value": 22.22,
"Text": 8.65,
"Common": 1.10,
"Editable": "true",
"Insert": 6.0
}]
}
The keys in data will not always be the same (i've just used examples, there are 20 different keys), and as such, I cannot set up my script to statically reference them to get the values.
Otherwise I could state
var value1 = json.data.Timestamp;
var value2 = json.data.Start_Value;
var value3 = json.data.Abstract;
etc
In the past i've used a simple foreach loop on the data node...
foreach ($json->data as $key => $val) {
switch($key) {
case 'Timestamp':
//do this;
case: 'Start_Value':
//do this
}
}
But don't want to block the script. Any ideas?
You can iterate through JavaScript objects this way:
for(var attributename in myobject){
console.log(attributename+": "+myobject[attributename]);
}
myobject could be your json.data
I would recommend taking advantage of the fact that nodeJS will always be ES5. Remember this isn't the browser folks you can depend on the language's implementation on being stable. That said I would recommend against ever using a for-in loop in nodeJS, unless you really want to do deep recursion up the prototype chain. For simple, traditional looping I would recommend making good use of Object.keys method, in ES5. If you view the following JSPerf test, especially if you use Chrome (since it has the same engine as nodeJS), you will get a rough idea of how much more performant using this method is than using a for-in loop (roughly 10 times faster). Here's a sample of the code:
var keys = Object.keys( obj );
for( var i = 0,length = keys.length; i < length; i++ ) {
obj[ keys[ i ] ];
}
You may also want to use hasOwnProperty in the loop.
for (var prop in obj) {
if (obj.hasOwnProperty(prop)) {
switch (prop) {
// obj[prop] has the value
}
}
}
node.js is single-threaded which means your script will block whether you want it or not. Remember that V8 (Google's Javascript engine that node.js uses) compiles Javascript into machine code which means that most basic operations are really fast and looping through an object with 100 keys would probably take a couple of nanoseconds?
However, if you do a lot more inside the loop and you don't want it to block right now, you could do something like this
switch (prop) {
case 'Timestamp':
setTimeout(function() { ... }, 5);
break;
case 'Start_Value':
setTimeout(function() { ... }, 10);
break;
}
If your loop is doing some very CPU intensive work, you will need to spawn a child process to do that work or use web workers.
If you want to avoid blocking, which is only necessary for very large loops, then wrap the contents of your loop in a function called like this: process.nextTick(function(){<contents of loop>}), which will defer execution until the next tick, giving an opportunity for pending calls from other asynchronous functions to be processed.
My most preferred way is,
var objectKeysArray = Object.keys(yourJsonObj)
objectKeysArray.forEach(function(objKey) {
var objValue = yourJsonObj[objKey]
})
If we are using nodeJS, we should definitely take advantage of different libraries it provides. Inbuilt functions like each(), map(), reduce() and many more from underscoreJS reduces our efforts. Here's a sample
var _=require("underscore");
var fs=require("fs");
var jsonObject=JSON.parse(fs.readFileSync('YourJson.json', 'utf8'));
_.map( jsonObject, function(content) {
_.map(content,function(data){
if(data.Timestamp)
console.log(data.Timestamp)
})
})
A little late but I believe some further clarification is given below.
You can iterate through a JSON array with a simple loop as well, like:
for(var i = 0; i < jsonArray.length; i++)
{
console.log(jsonArray[i].attributename);
}
If you have a JSON object and you want to loop through all of its inner objects, then you first need to get all the keys in an array and loop through the keys to retrieve objects using the key names, like:
var keys = Object.keys(jsonObject);
for(var i = 0; i < keys.length; i++)
{
var key = keys[i];
console.log(jsonObject.key.attributename);
}
Not sure if it helps, but it looks like there might be a library for async iteration in node hosted here:https://github.com/caolan/async
Async is a utility module which provides straight-forward, powerful functions for working with asynchronous JavaScript. Although originally designed for use with node.js, it can also be used directly in the browser.
Async provides around 20 functions that include the usual 'functional' suspects (map, reduce, filter, forEach…) as well as some common patterns for asynchronous control flow (parallel, series, waterfall…). All these functions assume you follow the node.js convention of providing a single callback as the last argument of your async function.
Take a look at Traverse. It will recursively walk an object tree for you and at every node you have a number of different objects you can access - key of current node, value of current node, parent of current node, full key path of current node, etc. https://github.com/substack/js-traverse. I've used it to good effect on objects that I wanted to scrub circular references to and when I need to do a deep clone while transforming various data bits. Here's some code pulled form their samples to give you a flavor of what it can do.
var id = 54;
var callbacks = {};
var obj = { moo : function () {}, foo : [2,3,4, function () {}] };
var scrubbed = traverse(obj).map(function (x) {
if (typeof x === 'function') {
callbacks[id] = { id : id, f : x, path : this.path };
this.update('[Function]');
id++;
}
});
console.dir(scrubbed);
console.dir(callbacks);
I am using 0.3.1-pre Node.js
Doing this:
typeof global.parseInt
results in
'undefined'
However when pressing [Tab] in the console after typing 'global.' gives a list of functions, including parseInt.
So is parseInt a member of the global namespace or not?
As of NodeJS v0.8.14 global seems to work across modules like the window object does in the browser.
Test:
a.js:
a1 = console.log; // Will be accessed from b.js
global.a2 = console.log; // Will be accessed from b.js
require('./b.js');
b1('a: b1');
b2('a: b2');
global.b1('a: global.b1');
global.b2('a: global.b2');
b.js:
a1('b: a1');
a2('b: a2');
global.a1('b: global.a1');
global.a2('b: global.a2');
b1 = console.log; // Will be accessed from a.js
global.b2 = console.log; // Will be accessed from a.js
Running a.js outputs:
b: a1
b: a2
b: global.a1
b: global.a2
a: b1
a: b2
a: global.b1
a: global.b2
Apparently, the global object isn't the global object as window is in the browser. It's (according to micheil in #nodejs # freenode) really only used internally. Something about global closures and whatnot.
parseInt and setTimeout and all those buddies are globals on their own. Not part of any visible global object.
Defining variable in app.js without var, just like myvar='someval' makes it visible inside every .js in your project
FAILS:
if( global[ some_object_i_want_to_exist ] ){ ... }
WORKS:
//: outside of all functions, including IIFE.
const THE_GLOBAL_YOU_PROBABLY_WANT_IS_THIS=( this );
//: Within a function:
const G = THE_GLOBAL_YOU_PROBABLY_WANT_IS_THIS;
if( G[ some_object_i_want_to_exist ] ){ ... }
I am assuming you got to this page about "global" in node.js because you wanted the equivalent of "window" in order to check for globally declared variables. bFunc's solution didn't work for me, as it seems to require that one explicitly does something like:
global.some_object_i_want_to_exist = whatever;
as a pre-requisit to using
global[ some_object_i_want_to_exist ]
EDIT: Looking at my code it seems that the only reason my solution worked is because I used "exports.some_object_i_want_to_exist" somewhere else in the
file. Without that, my solution fails. So... I have no clue how to reliable determine if an object exists in a given scope in Node.js.
Here is the documentation on global object:
https://nodejs.org/api/globals.html
I am going to leave my answer here because I hear people are more likely to correct you when you are wrong, so maybe someone will correct me with the answer to the problem.