I'm trying to update an array every time my tag receives an update from parent tags. Here is my code:
var tag = function(opts){
this.set = [];
var self = this;
this.on('updated', function(){
var obj = opts.my_topics;
var better_obj = {};
for (var key in obj) {
if (obj.hasOwnProperty(key)) {
var topic_title = key;
better_obj = obj[key];
better_obj['title'] = key;
}
}
self.set.push(better_obj);
})
}
Whenever I try to push(), I get an error: Uncaught SyntaxError: Unexpected token ; database.js:60. The moment I remove the line of code for the push, the error disappears. Am I using this/self wrong in this case or could it be something else?
What I am trying to accomplish here is taking an object from opts (which receives regular updates), converting into an array, and using it for an each loop within my tag. I do not know how to do this other than a) what i'm trying to do now by accessing this, or b) rewiring my opts to deliver an array rather than an object (which is currently failing for me as I'm using Redux and it doesn't like dispatching non-objects).
Related
I need to return an array of labels, but I can only return 1 of the labels so far. The error which I get is "Cannot set headers after they are sent to the client". So I tried res.write and placed res.end after my for loop then I get the obvious error of doing a res.end before a res.write. How do I solve this?
for(let i=0;i<arr.length;i++){
request.get(arr[i], function (error, response, body) {
if (!error && response.statusCode == 200) {
myfunction();
async function myfunction(){
const Labels = await Somefunctioncallwhoseresponseigetlater(body)
res.send(Labels);
}
}
});}
New code-
async function getDataSendResponse(res) {
let allLabels = [];
for (let url of arr) {
let body = await got(url).buffer();
var imgbuff= Buffer.from(body,'base64')
const imageLabels = await rekognition.detectLabels(imgbuff);
allLabels.push(...imageLabels);
}
res.send(allLabels);
}
The error I have with this code is
"Resolver: AsyncResolver
TypeError: Cannot destructure property Resolver of 'undefined' or 'null'."
You are trying to call res.send() inside a for loop. That means you'll be trying to call it more than once. You can't do that. You get to send one response for any given http request and res.send() sends an entire response. So, when you try to call it again inside the loop, you can the warning you see.
If what you're trying to do is to send an array of labels, then you need to accumulate the array of labels first and then make one call to res.send() to send the final array.
You don't show the whole calling context here, but making the following assumptions:
Somefunctioncallwhoseresponseigetlater() returns a promise that resolves when it is done
You want to accumulate all the labels you collected in your loop
Your Labels variable is an array
Your http request returns a text response. If it returns something else like JSON, then .text() would need to be changed to .json().
then you can do it like this:
const got = require('got');
async function getDataSendResponse(res) {
let allLabels = [];
for (let url of arr) {
let body = await got(url).buffer();
const labels = await Somefunctioncallwhoseresponseigetlater(body);
allLabels.push(...labels);
}
res.send(allLabels);
}
Note, I'm using the got() library instead of the deprecated request() library both because request() is not deprecated and because this type of code is way easier when you have an http library that supports promises (like got() does).
I have a Vuex getter like this:
sectionsAndSubSectionsJoined(state) {
var sections = state.aBMudbone.sections;
var subsections = state.aBMudbone.subSections;
var combinedSections = [];
_.forEach(sections, function (section) {
var subSectionsFiltered = _.filter(subsections, ['sectionId', section.sectionId]);
var sectionAndSubSections = section;
sectionAndSubSections.children = subSectionsFiltered;
combinedSections.push(sectionAndSubSections);
});
return combinedSections
}
In the console I get the following error:
[vuex] do not mutate vuex store state outside mutation handlers.
The line it shows this error for is :
sectionAndSubSections.children = subSectionsFiltered;
As I understand it, even though sections, subSections and sectionAndSubSections are new objects, because they are created from the store state they are subject to some binding hence the warning when I try to add to this state.
How can I disconnect this new state from the store state so I don't get this warning?
I have a table which gets its data server-side, using custom server-side initialization params which vary depending upon which report is produced. Once the table is generated, the user may open a popup in which they can add multiple additional filters on which to search. I need to be able to use the same initialization params as the original table, and add the new ones using fnServerParams.
I can't figure out how to get the original initialization params using the datatables API. I had thought I could get a reference to the object, get the settings using fnSettings, and pass those settings into a new datatables instance like so:
var oSettings = $('#myTable').dataTable().fnSettings();
// add additional params to the oSettings object
$('#myTable').dataTable(oSettings);
but the variable returned through fnSettings isn't what I need and doesn't work.
At this point, it seems like I'm going to re-architect things so that I can pass the initialization params around as a variable and add params as needed, unless somebody can steer me in the right direction.
EDIT:
Following tduchateau's answer below, I was able to get partway there by using
var oTable= $('#myTable').dataTable(),
oSettings = oTable.fnSettings(),
oParams = oTable.oApi._fnAjaxParameters(oSettings);
oParams.push('name':'my-new-filter', 'value':'my-new-filter-value');
and can confirm that my new serverside params are added on to the existing params.
However, I'm still not quite there.
$('#myTable').dataTable(oSettings);
gives the error:
DataTables warning(table id = 'myTable'): Cannot reinitialise DataTable.
To retrieve the DataTables object for this table, please pass either no arguments
to the dataTable() function, or set bRetrieve to true.
Alternatively, to destroy the old table and create a new one, set bDestroy to true.
Setting
oTable.bRetrieve = true;
doesn't get rid of the error, and setting
oSettings.bRetrieve = true;
causes the table to not execute the ajax call. Setting
oSettings.bDestroy = true;
loses all the custom params, while setting
oTable.bDestroy = true;
returns the above error. And simply calling
oTable.fnDraw();
causes the table to be redrawn with its original settings.
Finally got it to work using fnServerParams. Note that I'm both deleting unneccessary params and adding new ones, using a url var object:
"fnServerParams": function ( aoData ) {
var l = aoData.length;
// remove unneeded server params
for (var i = 0; i < l; ++i) {
// if param name starts with bRegex_, sSearch_, mDataProp_, bSearchable_, or bSortable_, remove it from the array
if (aoData[i].name.search(/bRegex_|sSearch_|mDataProp_|bSearchable_|bSortable_/) !== -1 ){
aoData.splice(i, 1);
// since we've removed an element from the array, we need to decrement both the index and the length vars
--i;
--l;
}
}
// add the url variables to the server array
for (i in oUrlvars) {
aoData.push( { "name": i, "value": oUrlvars[i]} );
}
}
This is normally the right way to retrieve the initialization settings:
var oSettings = oTable.fnSettings();
Why is it not what you need? What's wrong with these params?
If you need to filter data depending on your additional filters, you can complete the array of "AJAX data" sent to the server using this:
var oTable = $('#myTable').dataTable();
var oParams = oTable.oApi._fnAjaxParameters( oTable );
oParams.push({name: "your-additional-param-name", value: your-additional-param-value });
You can see some example usages in the TableTools plugin.
But I'm not sure this is what you need... :-)
I am trying to develop a search filter and making use of the HTML5 history API to reduce the number of requests sent to the server. If the user checks a checkbox to apply a certain filter I am saving that data in the history state, so that when the user unchecks it I am able to load the data back from the history rather than fetching it again from the server.
When the user checks or unchecks a filter I am changing the window URL to match the filter that was set, for instance if the user tries to filter car brands only of a certain category I change the URL like 'cars?filter-brand[]=1'.
But when mutiple filters are applied I have no way of figuring out whether to load the data from the server or to load it from the history.
At the moment I am using the following code.
pushString variable is the new query string that will be created.
var back = [],forward = [];
if(back[back.length-1] === decodeURI(pushString)){ //check last back val against the next URL to be created
back.pop();
forward.push(currentLocation);
history.back();
return true;
}else if(forward[forward.length-1] === decodeURI(pushString)){
forward.pop();
back.push(currentLocation);
history.forward();
return true;
}else{
back.push(currentLocation); //add current win location
}
You can check if your filters are equivalent.
Comparing Objects
This is a simple function that takes two files, and lets you know if they're equivalent (note: not prototype safe for simplicity).
function objEqual(a, b) {
function toStr(o){
var keys = [], values = [];
for (k in o) {
keys.push(k);
values.push(o[k]);
}
keys.sort();
values.sort();
return JSON.stringify(keys)
+ JSON.stringify(values);
}
return toStr(a) === toStr(b);
}
demo
Using the URL
Pass the query part of the URL (window.location.search) to this function. It'll give you an object you can compare to another object using the above function.
function parseURL(url){
var obj = {}, parts = url.split("&");
for (var i=0, part; part = parts[i]; i++) {
var x = part.split("="), k = x[0], v = x[1];
obj[k] = v;
}
return obj;
}
Demo
History API Objects
You can store the objects with the History API.
window.history.pushState(someObject, "", "someURL")
You can get this object using history.state or in a popState handler.
Keeping Track of Things
If you pull out the toStr function from the first section, you can serialize the current filters. You can then store all of the states in an object, and all of the data associated.
When you're pushing a state, you can update your global cache object. This code should be in the handler for the AJAX response.
var key = toStr(parseUrl(location.search));
cache[key] = dataFromTheServer;
Then abstract your AJAX function to check the cache first.
function getFilterResults(filters, callback) {
var cached = cache[toStr(filters)]
if (cached != null) callback(cached);
else doSomeAJAXStuff().then(callback);
}
You can also use localstorage for more persistent caching, however this would require more advanced code, and expiring data.
I'm looking into using a javascript logging framework in my app.
I quite like the look of log4javascript (http://log4javascript.org/) but I have one requirement which I'm not sure that it satisfies.
I need to be able to ask the framework for all messages which have been logged.
Perhaps I could use an invisible InPageAppender (http://log4javascript.org/docs/manual.html#appenders) to log to a DOM element, then scrape out the messages from that DOM element - but that seems pretty heavy.
Perhaps I need to write my own "InMemoryAppender"?
There's an ArrayAppender used in log4javascript's unit tests that stores all log messages it receives in an array accessible via its logMessages property. Hopefully it should show up in the main distribution in the next version. Here's a standalone implementation:
var ArrayAppender = function(layout) {
if (layout) {
this.setLayout(layout);
}
this.logMessages = [];
};
ArrayAppender.prototype = new log4javascript.Appender();
ArrayAppender.prototype.layout = new log4javascript.NullLayout();
ArrayAppender.prototype.append = function(loggingEvent) {
var formattedMessage = this.getLayout().format(loggingEvent);
if (this.getLayout().ignoresThrowable()) {
formattedMessage += loggingEvent.getThrowableStrRep();
}
this.logMessages.push(formattedMessage);
};
ArrayAppender.prototype.toString = function() {
return "[ArrayAppender]";
};
Example use:
var log = log4javascript.getLogger("main");
var appender = new ArrayAppender();
log.addAppender(appender);
log.debug("A message");
alert(appender.logMessages);