Kernel API
Package: @tao.js/core
Named Export: Kernel
The Kernel is the base entry point of execution for tao.js apps. Application Contexts are set on a
Kernel which then calls out to handlers which have been registered to trigrams that match the
Application Context.
Methods
constructor
| arg | required | type | default | description |
|---|---|---|---|---|
handlers |
no | Map |
used for cloning a Kernel when instantiated - should change to another Kernel |
|
canSetWildcard |
no | boolean | false |
set to true to allow the Kernel to accept wildcard AppCons to be set |
Used to construct a Kernel for use in an application. Any app importing the @tao.js/core package
will have a default Kernel available as the default import from the package.
Use the Kernel constructor to instantiate additional Kernels to have separated buses on which to
set AppCons.
setCtx
| arg | required | type | default | description |
|---|---|---|---|---|
trigram |
yes & no | Object |
the trigram representing the Application Context being set | |
data |
no | Object or Array |
data associated with the Application Context being set |
If canSetWildcard is false for the Kernal (which is the default), then all trigram args that do
not specify all 3 values will be silently ignored.
trigram is an object with keys specifying which Application Context is being set:
t/term- the term for the trigrama/action- the action for the trigramo/orient- the orient(ation) for the trigram
data is used to set a specific Application Context by specifying what the AppCon is being set for.
If not supplied as an arg, data will not be associated with the Application Context but an empty
object will always be used when calling the handlers to prevent having to check for undefined.
data follows the same rules as for the AppCtx constructor.
Not true: currently it only accepts being a single argument rather than a series of up to 3 -
this should be changed for consistency?
When called, setCtx calls all of the handlers attached to the Kernel that match the trigram of
the Application Context in the guaranteed order of operations.
setAppCtx
| arg | required | type | default | description |
|---|---|---|---|---|
appCtx |
yes | AppCtx |
the Application Context being set |
If canSetWildcard is false for the Kernal (which is the default), then all appCtx args that do
not specify all 3 parts of a trigram will be silently ignored.
When called, setCtx calls all of the handlers attached to the Kernel that match the trigram of
the Application Context in the guaranteed order of operations.
addInterceptHandler
| arg | required | type | default | description |
|---|---|---|---|---|
trigram |
no | Object |
All wild trigram | the trigram matching Application Contexts that should be sent to this Intercept Handler |
handler |
yes | function |
a handler function that will be called when an Application Context matching the trigram is set on the Kernel |
returns: Kernel - a reference to the Kernel that was called for chaining
trigram is an object with keys specifying which Application Contexts will be sent to the handler:
t/term- the term for the trigrama/action- the action for the trigramo/orient- the orient(ation) for the trigram
If trigram is not provided, is empty, or does not have the correct keys, it will default to
Wildcard keys for the parts of the trigram that are missing.
Intercept Handlers have specific behavior defined in the Advanced > Intercept Handlers section of the Guide.
addAsyncHandler
| arg | required | type | default | description |
|---|---|---|---|---|
trigram |
no | Object |
All wild trigram | the trigram matching Application Contexts that should be sent to this Async Handler |
handler |
yes | function |
a handler function that will be called when an Application Context matching the trigram is set on the Kernel |
returns: Kernel - a reference to the Kernel that was called for chaining
trigram is an object with keys specifying which Application Contexts will be sent to the handler:
t/term- the term for the trigrama/action- the action for the trigramo/orient- the orient(ation) for the trigram
If trigram is not provided, is empty, or does not have the correct keys, it will default to
Wildcard keys for the parts of the trigram that are missing.
Async Handlers have specific behavior defined in the Advanced > Async Handlers section of the Guide.
addInlineHandler
| arg | required | type | default | description |
|---|---|---|---|---|
trigram |
no | Object |
All wild trigram | the trigram matching Application Contexts that should be sent to this Inline Handler |
handler |
yes | function |
a handler function that will be called when an Application Context matching the trigram is set on the Kernel |
returns: Kernel - a reference to the Kernel that was called for chaining
trigram is an object with keys specifying which Application Contexts will be sent to the handler:
t/term- the term for the trigrama/action- the action for the trigramo/orient- the orient(ation) for the trigram
If trigram is not provided, is empty, or does not have the correct keys, it will default to
Wildcard keys for the parts of the trigram that are missing.
Inline Handlers have specific behavior defined in the Advanced > Inline Handlers section of the Guide.
removeInterceptHandler
| arg | required | type | default | description |
|---|---|---|---|---|
trigram |
no | Object |
All wild trigram | the trigram matching Application Contexts that should not be sent to this Intercept Handler |
handler |
yes | function |
a handler function that has been attached to the Kernel |
returns: Kernel - a reference to the Kernel that was called for chaining
trigram is an object with keys specifying which Application Contexts this handler should no
longer receive:
t/term- the term for the trigrama/action- the action for the trigramo/orient- the orient(ation) for the trigram
If trigram is not provided, is empty, or does not have the correct keys, it will default to
Wildcard keys for the parts of the trigram that are missing.
If the handler is not attached to the provided trigram then the request is silently ignored.
removeAsyncHandler
| arg | required | type | default | description |
|---|---|---|---|---|
trigram |
no | Object |
All wild trigram | the trigram matching Application Contexts that should not be sent to this Async Handler |
handler |
yes | function |
a handler function that has been attached to the Kernel |
returns: Kernel - a reference to the Kernel that was called for chaining
trigram is an object with keys specifying which Application Contexts this handler should no
longer receive:
t/term- the term for the trigrama/action- the action for the trigramo/orient- the orient(ation) for the trigram
If trigram is not provided, is empty, or does not have the correct keys, it will default to
Wildcard keys for the parts of the trigram that are missing.
If the handler is not attached to the provided trigram then the request is silently ignored.
removeInlineHandler
| arg | required | type | default | description |
|---|---|---|---|---|
trigram |
no | Object |
All wild trigram | the trigram matching Application Contexts that should not be sent to this Inline Handler |
handler |
yes | function |
a handler function that has been attached to the Kernel |
returns: Kernel - a reference to the Kernel that was called for chaining
trigram is an object with keys specifying which Application Contexts this handler should no
longer receive:
t/term- the term for the trigrama/action- the action for the trigramo/orient- the orient(ation) for the trigram
If trigram is not provided, is empty, or does not have the correct keys, it will default to
Wildcard keys for the parts of the trigram that are missing.
If the handler is not attached to the provided trigram then the request is silently ignored.
asPromiseHook
| arg | required | type | default | description |
|---|---|---|---|---|
resolveOn |
yes & no | Object or Array |
single or list of trigrams on which to resolve the Promise |
|
rejectOn |
yes & no | Object or Array |
single or list of trigrams on which to reject the Promise |
|
timeoutMs |
no | number | 0 |
a timeout in milliseconds after which the Promise should be rejected |
returns: a setCtx function that will return a Promise which will resolve or reject based
on the arguments provided.
At least one of either resolveOn or rejectOn must be provided to asPromiseHook or an
Error will be thrown.
resolveOn and rejectOn are trigrams of the same form used by the add and remove handler methods
of the Kernel, an object with keys specifying which Application Contexts this handler should no
longer receive:
t/term- the term for the trigrama/action- the action for the trigramo/orient- the orient(ation) for the trigram
asPromiseHook adds Inline Handlers for each of the trigrams provided to it in the resolveOn
and rejectOn args and cleans up after itself by removing those handlers just before resolving or
rejecting the Promise.
asPromiseHook is late binding, meaning that it will add the handlers to the Kernel only after
the returned setCtx function is called so that the handlers aren't called/executed until
desired.