Re: Util
Derek Caisse
Takes an async function (or a function that returns a Promise) and returns afunction following the error-first callback style, i.e. takingan (err, value) => ... callback as the last argument. In the callback, thefirst argument will be the rejection reason (or null if the Promiseresolved), and the second argument will be the resolved value.
Since null has a special meaning as the first argument to a callback, if awrapped function rejects a Promise with a falsy value as a reason, the valueis wrapped in an Error with the original value stored in a field namedreason.
The util.debuglog() method is used to create a function that conditionallywrites debug messages to stderr based on the existence of the NODE_DEBUGenvironment variable. If the section name appears within the value of thatenvironment variable, then the returned function operates similar toconsole.error(). If not, then the returned function is a no-op.
The util.debuglog().enabled getter is used to create a test that can be usedin conditionals based on the existence of the NODE_DEBUG environment variable.If the section name appears within the value of that environment variable,then the returned value will be true. If not, then the returned value will befalse.
When called, util.deprecate() will return a function that will emit aDeprecationWarning using the 'warning' event. The warning willbe emitted and printed to stderr the first time the returned function iscalled. After the warning is emitted, the wrapped function is called withoutemitting a warning.
If either the --no-deprecation or --no-warnings command-line flags areused, or if the process.noDeprecation property is set to true prior tothe first deprecation warning, the util.deprecate() method does nothing.
If the --trace-deprecation or --trace-warnings command-line flags are set,or the process.traceDeprecation property is set to true, a warning and astack trace are printed to stderr the first time the deprecated function iscalled.
If the format argument is not a format string, the output string's formatting is no longer dependent on the type of the first argument. This change removes previously present quotes from strings that were being output when the first argument was not a string.
The util.format() method returns a formatted string using the first argumentas a printf-like format string which can contain zero or more formatspecifiers. Each specifier is replaced with the converted value from thecorresponding argument. Supported specifiers are:
util.format() is a synchronous method that is intended as a debugging tool.Some input values can have a significant performance overhead that can block theevent loop. Use this function with care and never in a hot code path.
Returns the string name for a numeric error code that comes from a Node.js API.The mapping between error codes and error names is platform-dependent.See Common System Errors for the names of common errors.
This mainly adds some input validation on top ofObject.setPrototypeOf(constructor.prototype, superConstructor.prototype).As an additional convenience, superConstructor will be accessiblethrough the constructor.super_ property.
The util.inspect() method returns a string representation of object that isintended for debugging. The output of util.inspect may change at any timeand should not be depended upon programmatically. Additional options may bepassed that alter the result.util.inspect() will use the constructor's name and/or @@toStringTag to makean identifiable tag for an inspected value.
The showHidden option allows WeakMap and WeakSet entries to beinspected. If there are more entries than maxArrayLength, there is noguarantee which entries are displayed. That means retrieving the sameWeakSet entries twice may result in different output. Furthermore, entrieswith no remaining strong references may be garbage collected at any time.
Using this allows code to be written in a portable fashion, so that the custominspect function is used in an Node.js environment and ignored in the browser.The util.inspect() function itself is passed as third argument to the custominspect function to allow further portability.
The defaultOptions value allows customization of the default options used byutil.inspect. This is useful for functions like console.log orutil.format which implicitly call into util.inspect. It shall be set to anobject containing one or more valid util.inspect() options. Settingoption properties directly is also supported.
Returns an iterator over each of the name-value pairs in the parameters.Each item of the iterator is a JavaScript Array. The first item of the arrayis the name, the second item of the array is the value.
Provides a higher level API for command-line argument parsing than interactingwith process.argv directly. Takes a specification for the expected argumentsand returns a structured object with the parsed options and positionals.
The returned tokens are in the order encountered in the input args. Optionsthat appear more than once in args produce a token for each use. Short optiongroups like -xy expand to a token for each option. So -xxx producesthree tokens.
promisify() assumes that original is a function taking a callback as itsfinal argument in all cases. If original is not a function, promisify()will throw an error. If original is a function but its last argument is notan error-first callback, it will still be passed an error-firstcallback as its last argument.
Decodes the input and returns a string. If options.stream is true, anyincomplete byte sequences occurring at the end of the input are bufferedinternally and emitted after the next call to textDecoder.decode().
Listens to abort event on the provided signal andreturns a promise that is fulfilled when the signal isaborted. If the passed resource is garbage collected before the signal isaborted, the returned promise shall remain pending indefinitely.
util.types provides type checks for different kinds of built-in objects.Unlike instanceof or Object.prototype.toString.call(value), these checks donot inspect properties of the object that are accessible from JavaScript (liketheir prototype), and usually have the overhead of calling into C++.
The result generally does not make any guarantees about what kinds ofproperties or behavior a value exposes in JavaScript. They are primarilyuseful for addon developers who prefer to do type checking in JavaScript.
Returns true if the value is an async function.This only reports back what the JavaScript engine is seeing;in particular, the return value may not match the original source code ifa transpilation tool was used.
A native External value is a special type of object that contains araw C++ pointer (void*) for access from native code, and has no otherproperties. Such objects are created either by Node.js internals or nativeaddons. In JavaScript, they are frozen objects with anull prototype.
Returns true if the value is a generator function.This only reports back what the JavaScript engine is seeing;in particular, the return value may not match the original source code ifa transpilation tool was used.
Returns true if the value is a generator object as returned from abuilt-in generator function.This only reports back what the JavaScript engine is seeing;in particular, the return value may not match the original source code ifa transpilation tool was used.
A value being instanceof a native error class is not equivalent to isNativeError()returning true for that value. isNativeError() returns true for errorswhich come from a different realm while instanceof Error returns falsefor these errors:
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Getting more than a little fed up with issues on this Java course, that have no answers and no fix over a year on (have TTreehouse just left the Java course out to die a slow death?!?) . So any help much appreciated.
I have the same imports as you, but my code is not giving me unexpected errors yet (it's failing the test like it's supposed to). One of my project's Test Dependencies is junit-jupitar-api-5.6.0.jar, so I think I'm on junit5.
So I'll answer this myself as I have figured it out, in case it helps anyone else going forwards. Google told me: "Supplier is an in-built functional interface introduced in Java 8 in the java.util.function package"
Despite only having the latest JDK, for some reason when I used the tutorial files from GitHub the Project SDK was set to a ridiculously early version and the language level was too. Under Project structure, once I changed the JDK to 16, and also set the language level to either 8 or 16, then fail() worked without the error. So it is a language level issue I believe to be aware of if you are using the current files from Github.
So I see my testing message in the Help->Diagnostics->LogViewer, but I expect to also see it in the web interface Status-> Logs, where I have Scripting.ScriptManager.Project[TestLogger] set to Trace in Log Configuration.
I have a Vision Client that runs some extrememly convoluted shared gateway script. I need to start untangling it, and I thought logging some debug level messages to capture certain values after certain user actions would be extremely useful.
You say the user is running some convoluted gateway script - is it running it on the gateway via a message handler (or gateway tag change)? If so - those logs would in fact appear in the logs on your gateway webpage.
If you need the logged to the gateway, have the client send a message to a gateway message handler to run whatever you need on the gateway, and then whatever is logged in that context will be on your gateway logs.
and then from your client you can send it a payload (data pertinent to whatever you are running, if needed) via system.util.sendMessage - Ignition User Manual 8.0 - Ignition Documentation . Then, whatever happens inside that myMessageHanlder script def handleMessage(payload): - that is running on the gateway, not the client, and so any logging will go to the gateway logs.
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