Js Delphi DLL Reference Documentation
Js
Current Version: 11.4.0
Chilkat.Js is a small, embeddable JavaScript engine. It executes JavaScript code inside an application without requiring a browser or large runtime like Node.js. The Chilkat Js engine began as QuickJS, but after extensive redesign, refactoring, and hardening, it has evolved into a separate JavaScript engine maintained as part of the Chilkat platform.
See About the Chilkat.Js JavaScript Engine for more information.
This software includes portions of the QuickJS JavaScript engine Copyright (c) 2017-2024 Fabrice Bellard Licensed under the MIT License. The Chilkat Js engine was originally derived from QuickJS but has been extensively modified
Create/Dispose
var myObject: HCkJs; begin myObject := CkJs_Create(); // ... CkJs_Dispose(myObject); end;
Creates an instance of the HCkJs object and returns a handle (i.e. a Pointer). The handle is passed in the 1st argument for the functions listed on this page.
Objects created by calling CkJs_Create must be freed by calling this method. A memory leak occurs if a handle is not disposed by calling this function.
Properties
DebugLogFilePath
procedure CkJs_putDebugLogFilePath(objHandle: HCkJs; newPropVal: PWideChar); stdcall;
function CkJs__debugLogFilePath(objHandle: HCkJs): PWideChar; stdcall;
If set to a file path, this property logs the LastErrorText of each Chilkat method or property call to the specified file. This logging helps identify the context and history of Chilkat calls leading up to any crash or hang, aiding in debugging.
Enabling the VerboseLogging property provides more detailed information. This property is mainly used for debugging rare instances where a Chilkat method call causes a hang or crash, which should generally not happen.
Possible causes of hangs include:
- A timeout property set to 0, indicating an infinite timeout.
- A hang occurring within an event callback in the application code.
- An internal bug in the Chilkat code causing the hang.
See the notes about PWideChar memory ownership and validity.
LastErrorHtml
function CkJs__lastErrorHtml(objHandle: HCkJs): PWideChar; stdcall;
Provides HTML-formatted information about the last called method or property. If a method call fails or behaves unexpectedly, check this property for details. Note that information is available regardless of the method call's success.
See the notes about PWideChar memory ownership and validity.
topLastErrorText
function CkJs__lastErrorText(objHandle: HCkJs): PWideChar; stdcall;
Provides plain text information about the last called method or property. If a method call fails or behaves unexpectedly, check this property for details. Note that information is available regardless of the method call's success.
See the notes about PWideChar memory ownership and validity.
LastErrorXml
function CkJs__lastErrorXml(objHandle: HCkJs): PWideChar; stdcall;
Provides XML-formatted information about the last called method or property. If a method call fails or behaves unexpectedly, check this property for details. Note that information is available regardless of the method call's success.
See the notes about PWideChar memory ownership and validity.
topLastMethodSuccess
procedure CkJs_putLastMethodSuccess(objHandle: HCkJs; newPropVal: wordbool); stdcall;
Indicates the success or failure of the most recent method call: True means success, False means failure. This property remains unchanged by property setters or getters. This method is present to address challenges in checking for null or Nothing returns in certain programming languages. Note: This property does not apply to methods that return integer values or to boolean-returning methods where the boolean does not indicate success or failure.
TimeoutSeconds
procedure CkJs_putTimeoutSeconds(objHandle: HCkJs; newPropVal: Integer); stdcall;
Specify a timeout in seconds to prevent JavaScript from running indefinitely, such as in an infinite loop. By default, the value is 0, meaning no timeout is set and infinite loops will continue forever.
VerboseLogging
procedure CkJs_putVerboseLogging(objHandle: HCkJs; newPropVal: wordbool); stdcall;
If set to True, then the contents of LastErrorText (or LastErrorXml, or LastErrorHtml) may contain more verbose information. The default value is False. Verbose logging should only be used for debugging. The potentially large quantity of logged information may adversely affect peformance.
Version
function CkJs__version(objHandle: HCkJs): PWideChar; stdcall;
Version of the component/library, such as "10.1.0"
See the notes about PWideChar memory ownership and validity.
Methods
CallFunction
func: HCkJsonObject;
result: HCkJsonObject): wordbool; stdcall;
Calls a JavaScript function. The function name and arguments are passed in func. The result is returned in result.
Returns True for success, False for failure.
CallFunctionAsync (1)
func: HCkJsonObject;
result: HCkJsonObject): HCkTask; stdcall;
Creates an asynchronous task to call the CallFunction method with the arguments provided.
Note: Async method event callbacks happen in the background thread. Accessing and updating UI elements existing in the main thread may require special considerations.
Returns nil on failure
ConsoleOutputSb
Eval
jscript: HCkStringBuilder;
result: HCkJsonObject): wordbool; stdcall;
Run jscript as a script. Return output and errors in result.
Returns True for success, False for failure.
EvalAsync (1)
jscript: HCkStringBuilder;
result: HCkJsonObject): HCkTask; stdcall;
Creates an asynchronous task to call the Eval method with the arguments provided.
Note: Async method event callbacks happen in the background thread. Accessing and updating UI elements existing in the main thread may require special considerations.
Returns nil on failure
SetCkPermission
chilkatClassName: PWideChar;
permission: PWideChar): wordbool; stdcall;
Sets sandbox related permissions for Chilkat objects. The chilkatClassName is the name of the Chilkat class (case-insensitive), such as Http, Rest, "MailMan", "Ftp2", "Ssh", etc. The chilkatClassName can also be set to "all" to apply the permission to all Chilkat classes.
Possible values for permission are:
disable- Your JavaScript code is not allowed to create an instance of the Chilkat class. A JavaScript exception is thrown when trying to create a Chilkat object of a class that is disabled.sandbox- Objects for the Chilkat class can be instantiated in JavaScript, but they have no read or write access to the local filesystem.readOnly- Objects for the Chilkat class can be instantiated in JavaScript and have read-only access to the local filesystem.writeOnly- Objects for the Chilkat class can be instantiated in JavaScript and have write-only access to the local filesystem.readWrite- Objects for the Chilkat class can be instantiated in JavaScript and have read/write access to the local filesystem.
By default, all Chilkat classes are disabled. Your application must enable "all" or specific Chilkat classes before calling Eval or CallFunction .
Returns True for success, False for failure.
Events
AbortCheck
Enables a method call to be aborted by triggering the AbortCheck event at intervals defined by the HeartbeatMs property. If HeartbeatMs is set to its default value of 0, no events will occur. For instance, set HeartbeatMs to 200 to trigger 5 AbortCheck events per second. Return True to abort; return False to continue (not abort)
PercentDone
This provides the percentage completion for any method involving network communications or time-consuming processing, assuming the progress can be measured as a percentage. This event is triggered only when it's possible and logical to express the operation's progress as a percentage. The pctDone argument will range from 1 to 100. For methods that finish quickly, the number of PercentDone callbacks may vary, but the final callback will have pctDone equal to 100. For longer operations, callbacks will not exceed one per percentage point (e.g., 1, 2, 3, ..., 98, 99, 100).
The PercentDone callback also acts as an AbortCheck event. For fast methods where PercentDone fires, an AbortCheck event may not trigger since the PercentDone callback already provides an opportunity to abort. For longer operations, where time between PercentDone callbacks is extended, AbortCheck callbacks enable more responsive operation termination.
Return True to abort; return False to continue (not abort)
ProgressInfo
This event callback provides tag name/value pairs that detail what occurs during a method call. To discover existing tag names, create code to handle the event, emit the pairs, and review them. Most tag names are self-explanatory.
TaskCompleted
Called from the background thread when an asynchronous task completes.