Class: ConnectionChecker

Defined in: packages/blockly/core/connection_checker.ts:26

Class for connection type checking logic.

Implements

• IConnectionChecker

Methods index

Method	Description
canConnect	Check whether the current connection can connect with the target connection.
canConnectWithReason	Checks whether the current connection can connect with the target connection, and return an error code if there are problems.
getErrorMessage	Helper method that translates a connection error code into a string.
doSafetyChecks	Check that connecting the given connections is safe, meaning that it would not break any of Blockly's basic assumptions (e.g. no self connections).
doTypeChecks	Check whether this connection is compatible with another connection with respect to the value type system. E.g. square_root("Hello") is not compatible.
doDragChecks	Check whether this connection can be made by dragging.
canConnectToPrevious_	Helper function for drag checking.

Constructors

Constructor

new ConnectionChecker(): ConnectionChecker;

Returns

ConnectionChecker

Methods

canConnect()

canConnect(
   a, 
   b, 
   isDragging, 
   opt_distance?
): boolean;

Defined in: packages/blockly/core/connection_checker.ts:38

Check whether the current connection can connect with the target connection.

Parameters

Parameter	Type	Description
a	Connection | null	Connection to check compatibility with.
b	Connection | null	Connection to check compatibility with.
isDragging	boolean	True if the connection is being made by dragging a block.
opt_distance?	number	The max allowable distance between the connections for drag checks.

Returns

boolean

Whether the connection is legal.

Implementation of

IConnectionChecker.canConnect

---

canConnectWithReason()

canConnectWithReason(
   a, 
   b, 
   isDragging, 
   opt_distance?
): number;

Defined in: packages/blockly/core/connection_checker.ts:62

Checks whether the current connection can connect with the target connection, and return an error code if there are problems.

Parameters

Parameter	Type	Description
a	Connection | null	Connection to check compatibility with.
b	Connection | null	Connection to check compatibility with.
isDragging	boolean	True if the connection is being made by dragging a block.
opt_distance?	number	The max allowable distance between the connections for drag checks.

Returns

number

Connection.CAN_CONNECT if the connection is legal, an error code otherwise.

Implementation of

IConnectionChecker.canConnectWithReason

---

getErrorMessage()

getErrorMessage(
   errorCode, 
   a, 
   b
): string;

Defined in: packages/blockly/core/connection_checker.ts:102

Helper method that translates a connection error code into a string.

Parameters

Parameter	Type	Description
errorCode	number	The error code.
a	Connection | null	One of the two connections being checked.
b	Connection | null	The second of the two connections being checked.

Returns

string

A developer-readable error string.

Implementation of

IConnectionChecker.getErrorMessage

---

doSafetyChecks()

doSafetyChecks(a, b): number;

Defined in: packages/blockly/core/connection_checker.ts:148

Check that connecting the given connections is safe, meaning that it would not break any of Blockly's basic assumptions (e.g. no self connections).

Parameters

Parameter	Type	Description
a	Connection | null	The first of the connections to check.
b	Connection | null	The second of the connections to check.

Returns

number

An enum with the reason this connection is safe or unsafe.

Implementation of

IConnectionChecker.doSafetyChecks

---

doTypeChecks()

doTypeChecks(a, b): boolean;

Defined in: packages/blockly/core/connection_checker.ts:203

Check whether this connection is compatible with another connection with respect to the value type system. E.g. square_root("Hello") is not compatible.

Parameters

Parameter	Type	Description
a	Connection	Connection to compare.
b	Connection	Connection to compare against.

Returns

boolean

True if the connections share a type.

Implementation of

IConnectionChecker.doTypeChecks

---

doDragChecks()

doDragChecks(
   a, 
   b, 
   distance
): boolean;

Defined in: packages/blockly/core/connection_checker.ts:229

Check whether this connection can be made by dragging.

Parameters

Parameter	Type	Description
a	RenderedConnection	Connection to compare (on the block that's being dragged).
b	RenderedConnection	Connection to compare against.
distance	number	The maximum allowable distance between connections.

Returns

boolean

True if the connection is allowed during a drag.

Implementation of

IConnectionChecker.doDragChecks

---

canConnectToPrevious_()

protected canConnectToPrevious_(a, b): boolean;

Defined in: packages/blockly/core/connection_checker.ts:316

Helper function for drag checking.

Parameters

Parameter	Type	Description
a	Connection	The connection to check, which must be a statement input or next connection.
b	Connection	A nearby connection to check, which must be a previous connection.

Returns

boolean

True if the connection is allowed, false otherwise.