So I'm just getting to grips with node-red and I need to create a conditional global function.
I have two separate global.payloads set to a number value of either 0 or 1.
What I need to happen now is, if global.payload is equal to value 1 then follow this flow, if it is equal to value 0 then follow this one.
I'm just a little confused with the syntax for the function statement. Any help gratefully appreciated.
Since you haven't accepted the current answer, thought I'd give this a try.
I think this is what you need to handle inputs from two separate global contexts. I'm simulating them here with two separate inject nodes to demonstrate:
The checkconf inject node emits a 1 or a 0. Same for the meshstatus node. Substitute your real inputs for those inject nodes. The real work is done inside the function:
var c = context.get('c') || 0; // initialize variables
var m = context.get('m') || 0;
if (msg.topic == "checkconf") // update context based on topic of input
{
c = {payload: msg.payload};
context.set("c", c); // save last value in local context
}
if (msg.topic == 'meshstatus') // same here
{
m = {payload: msg.payload};
context.set('m', m); // save last value in local context
}
// now do the test to see if both inputs are triggered...
if (m.payload == 1) // check last value of meshstatus first
{
if (c.payload == 1) // now check last value of checkconf
return {topic:'value', payload: "YES"};
}
else
return {topic:'value', payload: "NO"};
Be sure to set the "topic" property of whatever you use as inputs so the if statements can discriminate between the two input. Good luck!
You can use the Switch node to do this, rather than a Function node.
Related
I'm trying to figure out a way to build a progress bar with React. I have a forEach loop that iterates through an array of about 7,000 indexes. Each time I validate a row, I want to update a state variable with percentage completion (and render this on the page live). I've tried iterating through these indexes, and updating my state variable (hoping to update the page) in the loop but I'm realizing that will not work. I obviously can't do this with a normal variable as it will reset when the component re-renders. Can anyone give me some insight on this topic?
Thanks.
Here is a code snippet from what I'm looking at:
parsedAssets.forEach(asset => {
newAssetValidated = validateBulkUpload(asset, parsedAssets, assetList, accountLogged, jobSites);
!newAssetValidated.reject_err ? validatedAssetList.accepted.push(newAssetValidated) : validatedAssetList.rejected.push(newAssetValidated);
setStateAssets({ ...stateAssets, validatedAssetList });
});
}
So essentially, as each asset is either accepted or rejected we add it to "stateAssets", and I'm hoping to build the progress bar from the length of the combined arrays that are getting set in stateAssets. However, when the forEach loop is completed, only the last validated asset is getting set due to it not updating until the forEach loop is completed.
Personally I can't imagine such a heavy validation, that you need progress-bar, but anyway.
First solution is to separate validation itself from state update for progress-bar into separate "threads". But since JS is single threaded, you may use some tricks with setTimeout or setInterval functionality. It may be very tricky, and in general not recommended practice with React.
Another way is - to set the work into queue & process 1 item at a time.
As an example I would do it something like this:
function ComponentWithProgress({parsedAssets, setParsedAssets}) {
const [validatedAssetList, setValidatedAssetList] = useState([])
const [progress, setProgress] = useState(0)
const [toDo, setToDo] = useState([])
if(parsedAssets && parsedAssets.length>0) {
setToDo(parsedAssets)
// clear parsedAssets in parent component to: [], false, null ...
// so you put it into toDo only once
setParsedAssets([])
}
if(toDo.length > 0) {
const asset = toDo[0]
const newToDo = toDo.slice(1) // All but 0th element
const newAssetValidated = validateBulkUpload(asset);
setValidatedAssetList([ ...validatedAssetList, newAssetValidated ]);
setToDo(newToDo)
setProgress( newToDo.length / ( validatedAssetList.length + newToDo.length ) * 100 )
}
// ... Render here
// If you need only accepted
const accepted = validatedAssetList.filter(v => !v.reject_err)
}
This example maybe not work for you as is, because you didn't showed us the context, but the main idea is here.
I'm using reactjs.
I have a series of divs that are created that represent a employee's availability. When clicked, they will display the number. However, they all alert the number 25 instead of their number.
for (
var i = state.availability[day][0];
i <= state.availability[day][1];
i++
) {
tempdaySlot.push(
<div
key={"ena:" + TimeConverter(i)}
style={LocalStyles.daySlot}
onClick={() => alert(i)}
>
{TimeConverter(i)}
</div>
);
}
state.availability is a two dimensional array that holds a number between 1-24 that represents someone's availability (ex [9-17])
TimeConverter is a function that converts a 24 hour type number to the usual 12 hour format (17 = "5 pm")
tempdaySlot is just a temporary array before I put it into a state variable
Use let i instead of var i. var hoists variable to the parent scope, let creates block scope.
this is a hoisting issue, because you defined the i using var it will be hoisted to the top of the function body so the last value which is 25 will be the only thing stored in that variable and since the variable isn't destroyed because it's hoisted it will only show the latest value.
just use let instead of var its a good practice to use let and const instead of var now so try getting used it, it will save you a lot of headaches.
Tl;dr declare i using let, not var
The var keyword creates variables with function scope. However, when you create a closure (like your onClick function), the lexical environment is captured by reference. When you call that onClick function later, it gets the current value of i (which is 25, since that's where the loop stopped), not the value of i when you created the function.
The let keyword creates i with traditional scoping, so in effect a new i is created on each iteration of the loop which solves this problem.
See What's the difference between using "let" and "var"? for more.
I am trying to write a function in CAPL that takes a signal and calculates the physical value with the signal value, the signal factor and the signal offset.
This is how a simple gateway normally works:
message CAN1.myMessage1 myMessage1 = {DIR = RX};//message from the database
message CAN2.myMessage2 myMessage2 = {DIR = TX};//another message from the database
on message CAN1.*
{
if(this.id == myMessage1.id)
{
myMessage1 = this;
myMessage2.mySignalB = myMessage1.mySignalA * myMessage1.mySignalA.factor + myMessage1.mySignalA.offset;
}
}
And this is what I am trying to do:
...
on message CAN1.*
{
if(this.id ==myMessage1.id)
{
myMessage1 = this;
myMessage2.mySignalB = PhysicalValue(myMessage1.mySignalA);
}
}
double PhysicalValue(signal * s)
{
return s*s.factor+s.offset;
}
There are two problems with this code:
Firstly when I pass the signal as the parameter the compiler says that the types don't match. The second problem is that inside the function the attributes (factor and offset) are no longer recognized.
These problems might have something to do with the weird object-oriented-but-not-really nature of CAPL. The value of the signals can be accessed directly but it also has attributes?
int rawValue = myMessage1.mySignalA;
If you are familiar with C you might say that the problem is that I am specifying a pointer in the function but that I am not passing a pointer into it. But in CAPL there are no pointers and the * simply means anything.
Without the * I would have needed to use a specific signal which would have defeated the purpose of the function.
EDIT:
I have found the attribute .phys by now which does exactly what my demo function would have done.
double physValue = myMessage1.mySignalA.phys;
This has already made my code much shorter but there are other operations that I need to perform for multiple signals so being able to use signals as a function parameter would still be useful.
What you can do is this:
double PhysicalValue(signal * s)
{
// access signal by prepending a $
return $s.phys;
}
Call like this
on message CAN1.*
{
if(this.id ==myMessage1.id)
{
myMessage1 = this;
myMessage2.mySignalB = PhysicalValue(CAN1::myMessage1::mySignalA);
}
}
I.e. when you call your function, you have to provide the qualified name of the signal (with colons rather than dots). To my knowledge it is not possible to use myMessage1.mySignalA, since signals itself are not a CAPL datatype.
Apart from this, you might re-think whether you really should be using on message, but rather switch to on signal. Handling the signal values no matter with which message they are sent is done by CANoe's signal server.
Note that CANoe already has a function which does exactly what you're trying to do (multiplying by factor and adding offset). It's called getSignal:
on message CAN1.*
{
if(this.id == myMessage1.id)
{
myMessage2.mySignalB = getSignal(myMessage1::mySignalA);
}
}
Offsets and factors are defined in e.g. the DBC files.
I'm trying to do some re-factoring on my charts to make them re-usable using this as a guide: http://bost.ocks.org/mike/chart/
I'm having problems drawing the lines in my multi-line graph though - specifically passing the data to the x and y values. If I hard code the element names it works, but if I try to use the xValue and yValue objects this does not work. I'm assuming that this is because I'm trying to call a function within the parameter of an other object, but I'm not sure how to get around this. In the exmaple Mike uses d[0] and d[1], but this won't work with JSON data (or I'm not sure how to make it work).
I've posted this JSFiddle so you can see the code. The problem lines are 125 to 131 which in turn is being called from line 165.
var main_line = d3.svg.line()
.interpolate("cardinal")
// Hard coding the elements works
//.x(function(d) { return main_x(d.date); })
//.y(function(d) { return main_y(d.buildFixTime); });
// Passing xValue and yValue does not work
.x(function(d) { return main_x(xValue); })
.y(function(d) { return main_y(yValue); });
http://jsfiddle.net/goodspeedj/fDyLY/
Thank you in advance.
You need to redefine your accessor method within .x() and .y(). The accessor method defines the way that a datum is pulled out of the data that is bound to the selection that you call the line generator on.
Suppose you have a relatively flat data structure such as the following.
data = [{x : 1, y : 2}, {x:1, y:3}, {x:4, y:5}];
You then bind the data to a selection with the following statement
d3.select("body").datum(data).append("path").attr("d",lineGenerator);
Quite a bit is going on underneath this statement. I'll give you a bit more of a walkthrough after showing you a commonly used example.
The important aspect to understand is that similarly to other calls in d3 such as
var exampleRectangles = d3.select("body")
.data(data).enter()
.append("rect")
.attr("width",2)
.attr("height", 3)
.attr("x",function(datum){return datum.x}) // pay attention to this line
.attr("y",0);
d3 is implicitly iterating over each element in your data. For each datum in your data array, in this case there is a total of three datum, you are going to add a rectangle to the dom.
In the line that I tell you to pay attention to you notice that you're defining an anonymous (unnamed) function. What is that datum parameter coming from? It's implicitly being passed to your anonymous function.
So each rectangle has it's own corresponding datum {x : 1, y : 2}, {x:1, y:3}, {x:4, y:5} respectively. Each rectangle's x coordinate is defined by the respective datum.x attribute. Under the sheets, d3 is implicitly looping over the data array that you've defined. A similar approach to the example d3 code could be written as above.
for (var i = 0; i < data.length; i++)
{
d3.select("body").append("rect")
.attr("width",2)
.attr("height", 3)
.attr("x",data[i].x)
.attr("y",0);
}
This follows from the notion of data driven documents (d3). For each item added (a rectangle in the above example a piece of data is tied to it. In the above example you see that there is something kind of similar to your .x() and .y() accessor functions :
.attr("x",function(datum){return datum.x})
This function is telling d3 how to filter over the total datum that's being passed to the .attr() accessor method.
So, you need to determine which data you need to get a hold of to make your .attr("d", lineGenerator)call make sense. The difference between your.datum(data)call and the typical.data(data)call is that instead of parceling the data that's being passed to.data(data)`, the whole array is given as a single piece of data to the line generator function (similar to main_line(data), wherein it will again implicitly loop over the points to construct your path.
So, what you need to do is determine what a single datum will be defined as for your function to operate on.
I'm not going to define that as I don't seem to know quite which information you are operating on, but I would hazard a guess at something like.
.x(xAccessor)
.y(yAccessor)
function xAccessor(datum)
{
return xScale(datum._id.month);
}
function yAccessor(datum)
{
return yScale(datum.buildFixTime);
}
The way you have it set up, xValue and yValue are functions; you have to actually execute them on something to get a value back.
.x(function(d) { return main_x( xValue(d) ); })
.y(function(d) { return main_y( yValue(d) ); });
If you weren't using a scale, you could use
.x(xValue)
.y(yValue);
but only because if you pass in a function d3 executes it for you with the data as a parameter. And that only works for d3 methods that expect functions as possible input -- the scale functions expect data values as input.
I wrote a long piece work for another user last week that you may find useful, explaining methods that accept functions as parameters.
My problem requires me to dynamically add where clauses to a IQueryable based on user input. The problem i'm having is that Linq-to-SQL doesn't seem to like having multiple where clauses on the same field, it actually duplicates the search arg value for the last item on all parameters. I verified this behavior through a SQL trace. Here is what I'm seeing.
WHERE ([t22].[OpenText] LIKE #p11) AND ([t22].[OpenText] LIKE #p12)
-- #p11: Input NVarChar (Size = 10; Prec = 0; Scale = 0) [%classify%] // Should be 2da57652-dcdf-4cc8-99db-436c15e5ef50
-- #p12: Input NVarChar (Size = 10; Prec = 0; Scale = 0) [%classify%]
My code uses a loop to dynamically add the where clauses as you can see below. My question is how do I work around this? This pretty much seems like a bug with the tool, no?
// add dyanmic where clauses based on user input.
MatchCollection searchTokens = Helper.ExtractTokensWithinBracePairs(filterText);
if (searchTokens.Count > 0)
{
foreach(Match searchToken in searchTokens)
query = query.Where((material => material.OpenText.Contains(searchToken.Value)));
}
else
{
query = query.Where((material => material.OpenText.Contains(filterText)));
}
Closing over the loop variable considered harmful! Change
foreach(Match searchToken in searchTokens) {
query = query.Where(
material => material.OpenText.Contains(searchToken.Value)
);
}
to
foreach(Match searchToken in searchTokens) {
Match token = searchToken;
query = query.Where(
material => material.OpenText.Contains(token.Value)
);
}
You are closing over the loop variable, which is considered harmful. To fix do this:
foreach(Match searchToken in searchTokens)
{
Match searchToken2 = searchToken;
// ^^^^^^^^^^^^ copy the value of the reference to a local variable.
query = query.Where(material => material.OpenText.Contains(searchToken2.Value));
// use the copy here ^^^^^^^^^^^^
}
The reason why your version doesn't work is that the query refers to the variable searchToken, not the value it had when the query was created. When the variable's value changes, all your queries see the new value.
I don't have enough rep to leave comments yet (or this would be a comment and not an answer) but the answers listed here worked for me.
However, I had to turn off compiler optimizations in order for it to work. If you do not turn off compiler optimizations (at least at the method level) then the compiler sees you setting a loop variable to a local variable and throws the local variable away.