var status = result.locations[index].status;
var operator = result.locations[index].operator;
var original = result.locations[index].original;
var produced = result.locations[index].produced;
var href = result.locations[index].more;
I have the above which each need to be an if statement to check if there is content and my output is the below code.
if (result.locations[index] && result.locations[index].status){
var status = result.locations[index].status;
} else {
var status = '';
}
I would need to reproduce this per line from the code at the top of the post. What would be the best method to simplify each down to keep the code neater and not produce 5 lines of if statement when 1 or 2 would do.
var status = (result.locations[index] && result.locations[index].status ? result.locations[index].status : '');
Not sure why you want to, but:
var status = (result.locations[index] && result.locations[index].status) ? result.locations[index].status : ""
Your problem is trying to access a property of a "deep" javascript object using its path.
This is a common question :
Javascript: Get deep value from object by passing path to it as string
Accessing nested JavaScript objects with string key
There is no built-in way to do this in javascript.
There are plenty of libraries to do that, for example, with selectn, this would become something like (I have not tested it, so I don't know if the index part will work, but you get the idea) :
var status = selectn("locations." + index + ".status", result) || ''
If the structure of your objects is always the one above (that is, the property is just at one level of depth), and you're not expecting 'falsy', you could simply write the 'test' function yourself :
function safeGet(instance, propertyName, defaultValue) {
// As pointed by AlexK, this will not work
// if instance[propertyName] can be anything Falsy ("", 0, etc...)
// If it's possible, get a library that will do
// the full series of insane checks for you ;)
if (instance && instance[propertyName)) {
return instance[propertyName];
} else {
return defaultValue;
}
}
var location = result.locations[index]; // Potentially undefined, but safeGet will deal with it
var status = safeGet(location, "status", "");
var operator = safeGet(location, "operator", "DEFAULT_OPERATOR");
...
var status = result.locations[index] && result.locations[index].status || '';
However, better maje sure before, if result.locations[index] exists... else do whatever is to be done in your code..
Related
Although, it ran fine on small data. I need help looping through JSON in this form:
var current_value = 2;
json_data = {"2":"first information","3":"Second informaton","4":"Third information"}
What I want to do is get the value in the json_data that corresponds to current_value of 2
The problem is that I keep getting " anytime I run this loop:
for(x in json_data){
if(x === current_value){
extracted = json_data[current_value];
}
}
JavaScript property names are strings. 2 is a number. === does not do type conversion. "2" !== 2.
You should set current_value to "2" instead of 2.
The loop is pointless though.
A more sensible approach would be:
var extracted;
if (current_value in json_data) {
extracted = json_data[current_value];
}
… or even just skip the if statement. extracted will be undefined either way if the property doesn't exist.
I have a list of objects as shown in the image.
These all have the property statusCode: 62467 but the journey property goes like: 0,1,2,3,3,4,4,4,4
I want to loop through these objects and return the FIRST of the duplicated (they are not the same object, just that both have the same journey number and the same status code) objects with the same journey number.
So I want to return the bold objects: 0,1,2,3,3,4,4,4,4
$.each(points, function (index, point) {
for (i = 0; i < journeyNumber.length; i++) {
if (point.k.journey === journeyNumber[i] && point.k.statusCode === '62467') {
console.log(point);
latlngs.push(point.j.aa.k);
latlngs.push(point.j.aa.B);
}
}
});
The screenshot is the log of console.log(point), so ideally I would like another loop inside which returns only the first object of the same journey number.
Hope this makes sense and thank you for your time.
Try this,
var temp = [];
$.each(points, function (index, point) {
if (temp.indexOf(point.k.journey) === -1) {
temp.push(point.k.journey);
console.log(point);
latlngs.push(point.j.aa.k);
latlngs.push(point.j.aa.B);
}
});
Create a fresh object with status codes and check against that.
var journeys = {};
for(object in points){
// extract the properties you want (or use them directly, this is not necessary)
var journey = points[object].journey;
var status = points[object].statusCode;
// use the typeof operator to see if the journey has already been set before
if(typeof journeys[journey] == "undefined"){
// then define it.
journeys[journey] = status;
}
}
(Please note I am not actually correctly referencing the journey and statusCode, you'd have to do something like objects[object][k].journey to access the right property, but thats not really the point)
You can even add anything you want into the journeys object, nesting another object with the extracted latitude and longitude, or even just nesting the entire object in the journey!
journeys[journey] = points[object];
Now you can get every journey by looping through them again, and the associated first statusCode:
for(journey in journeys){
console.log("First instance of journey " + journey + " had statusCode " + journeys[journey]);
}
I'm trying to handle an object which doesn't exist in the array.
var departureGate = JSON.stringify(data.flightStatuses[i].airportResources.departureGate);
So, when the javascript code gets here, it fall over because there happens to be nothing in the actual string it is trying to parse. I've tried catching it with "typeof", but that doesn't work either. I'm stumped.
So, the data.flightStatuses[i] array exists, just not the .airportResources.departureGate.
I tried to see if it exists using "typeof data.flightStatuses[i].airportResources.departureGate". It still falls over.
alert (typeof data.flightStatuses[i]) // this comes back "object"
alert (typeof data.flightStatuses[i].airportResources.departureGate) // it dies...
Should be fairly straight forward like this:
if (data.flightStatuses[i].airportResources.departureGate) {
var departureGate = JSON.stringify(data.flightStatuses[i].airportResources.departureGate);
}
It looks like your problem is with airportResources, and not with departureGate.
Try this:
var departureGate = null,
ar = data.flightStatuses[i].airportResources;
if(ar && 'departureGate' in ar){
departureGate = JSON.stringify(ar.departureGate);
}
Cheers
You can check if the departuregate is defined as a property at all like this, and then do the action you wanted, for example:
if(data.flightStatuses[i].airportResources.hasOwnProperty('departureGate') {
var departureGate = JSON.stringify(data.flightStatuses[i].airportResources.departureGate);
} else {
var departuregate = null; // for example
}
More info here: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object/hasOwnProperty
I found some days ago a really nice approach to parse css-strings (even nested) to json. However, it seems, that there's somewhere a big problem in it.
https://github.com/csvplot/cml-parse
If we try to parse a css-string, it will kill the browser window, don't know what's going on here... I already opend an issue but there's no one to answer the issue, since the maintainer David Ellis is lost.
Any ideas/suggestions?
function parse(data) {
var stateStack = [];
var scopeStack = [];
var outObj = {};
while(data) {
// Grab current number of indentation characters
/^(\s*)/.test(data);
// If we've entered any state, and that state is not an explicit block declaration ( {}'s ) and we have an indent level smaller than the most recent indent level,
// then remove the most recent scope level and recall the state back to the previous scope's state
if(stateStack.length &&
stateStack[stateStack.length-1] !== 'explicitBlock' &&
scopeStack.length &&
RegExp.$1.length < scopeStack[scopeStack.length-1].indent) {
scopeStack.pop();
while(stateStack.length && (stateStack[stateStack.length-1] !== 'block' || stateStack[stateStack.length-1] !== 'explicitBlock')) {
stateStack.pop();
}
}
// If current chunk is the key to an object
if(/^(\s*)([^:]*)\s*([{\n])/.test(data)) {
// Grab the indent size of the key and the current outObj position from the scope stack
var indentLength = RegExp.$1.length;
var currScope = (scopeStack.length ? scopeStack[scopeStack.length-1].ref : outObj);
// Split the identifier by spaces and construct/traverse down the defined path
// TODO: Figure out how to handle commas that define the same inner content along multiple paths
RegExp.$2.split(/\s*/).forEach(function(scope) {
if(scope !== '') {
currScope[scope] = currScope[scope] || {};
currScope = currScope[scope];
}
});
// Push the deepest scope and the current indent length onto the scope stack, and push the explicitBlock vs block state onto the state stack
// TODO: Work on a state diagram to truly handle all of the possible states involved properly
scopeStack.push({ref: currScope, indent: indentLength});
stateStack.push(RegExp.$3 === '{' ? 'explicitBlock' : 'block');
// Rip out the handled chunk of data from the string
data = data.replace(/^\s*[^:]*\s*[{\n]/, '');
}
}
return data;
}
http://fiddle.jshell.net/5pTBr/
Running the code, it looks like it just does not work.
It reaches an infinite loop since this regex is failing after the first run:
if(/^(\s*)([^:]*)\s*([{\n])/.test(data)) {
Hence why the browser is stuck. It also does not return the correct JSON.
I'd advise on writing something like this by yourself, or trying to debug and fix the existing code.
This is probably easy for someone.
I am returning a list of campaignIDs (12,45,66) via JSON to a javascript variable
var campaignList = res.DATA.CAMPAIGNS
Now, given a specified campaignID passed in the URL
var campaignId ='<cfoutput>#url.campaignID#</cfoutput>'
I want to check if the returned list contains this campaignID
Any help much appreciated.
Plenty of ways to do it, but I like nice data structures, so ...
Split the list on comma, then loop over list, looking for value:
function campaignExists(campaignList,campaignId) {
aCampaignList = campaignList.split(',');
for (i=0;i<aCampaignList.length;i++) {
if (aCampaignList[i]==campaignId)
return true;
}
return false;
}
Since Array.indexOf sadly isn't cross browser, you're looking at something like:
// assume there is no match
var match_found = false;
// iterate over the campaign list looking for a match,
// set "match_found" to true if we find one
for (var i = 0; i < campaignList.length; i += 1) {
if (parseInt(campaignList[i]) === parseInt(campaignId)) {
match_found = true;
break;
}
}
If you need to do this repeatedly, wrap it in a function
Here's a bit of a "out of the box" solution. You could create a struct for your property id's that you pass into the json searilizer have the key and the value the same. Then you can test the struct for hasOwnProperty. For example:
var campaignIDs = {12 : 12, 45 : 45, 66 : 66};
campaignIDs.hasOwnProperty("12"); //true
campaignIDs.hasOwnProperty("32"); //false
This way if the list is pretty long you wont have to loop through all of the potential properties to find a match. Here's a fiddle to see it in action:
http://jsfiddle.net/bittersweetryan/NeLfk/
I don't like Billy's answer to this, variables within the function have been declared in the global scope and it is somewhat over complicated. If you have a list of ids as a string in your js just search for the id you have from user input.
var patt = new RegExp("(^|,)" + campaignId + "(,|$)");
var foundCampaign = campaignList.search(patt) != -1;