Note the second function block first to get a better understanding.
So basically I have a large array of "tags" (variables) that are iterated through at the "for (let tag of tagArray) {...}" statement. The values of each of these "tags" is requested from a server asynchronously at "tagFunctionality.addGenericTag(tag.watchTag, function(value) {...}".
As I am receiving a lot of data, this process can become quite slow; to improve efficiency I proposed cancelling requests that I know will return a zero. After roughly ~1000 values the callback values start to become zeros in large chunks so I assume I can ignore these chunks and just default to zero instead of interpreting a zero value from the server, leading to a faster completion time. Currently I am forced to iterate through every value and wait for the server to return every value before proceeding. How can I successfully stop receiving particular asynchronous calls or something similar/more efficient?
(See my partial attempt at the "MY RECENT EDITION" comment.)
Function 1:
var repetitionLog = [];
var addGenericTag = function(tag, callback) {
// this spot runs before bulk data is received
currentSession.readVariableValue("ns=2;s=" + tag, function(err, dataValue) {
// this spot runs after bulk data is received
if (dataValue && dataValue.value) {
// MY RECENT EDITION: Detect chain of zeros
if (dataValue.value.value == 0) {
repetitionLog.push(dataValue.value.value)
// console.log(repetitionLog.length);
if (repetitionLog.length >= 1000) {
// this spot runs if 1000 zeros have been returned
// skip the next 100 callbacks and reset the repetition log or something
}
}
callback(dataValue.value.value);
} else {
callback(null);
}
});
}
Function 2:
var tagArray = []; // pretend this array is full of tags
var generateTagSystem = function(tagArray) {
var tagSystem = function() {
// Connect to this server
tagFunctionality.connect(function() {
// Subscribe to created session
tagFunctionality.start();
// IMPORTANT BIT, iterates over thousands of tags
for (let tag of tagArray) {
// Request value object of a particular tag
tagFunctionality.addGenericTag(tag.watchTag, function(value) {
// Tag is empty
if (value === null) {
// Tag value is empty, error code
// Tag is not empty or zero
} else if (value != 0) {
// Do something with tag code
// Tag is zero
} else {
// possibly useful future spot
}
});
}
});
};
tagSystem();
};