com.google.javascript.jscomp

Class RewriteAsyncIteration

java.lang.Object

com.google.javascript.jscomp.RewriteAsyncIteration

All Implemented Interfaces:

CompilerPass, HotSwapCompilerPass, NodeTraversal.Callback

public final class RewriteAsyncIteration
extends java.lang.Object
implements NodeTraversal.Callback, HotSwapCompilerPass

Converts async generator functions into a function returning a new $jscomp.AsyncGenWrapper around the original block and awaits/yields converted to yields of ActionRecords.

 async function* foo() {
   let res = await myPromise;
   yield res + 1;
 }
 

becomes (prefixes trimmed for clarity)

 function foo() {
   return new $jscomp.AsyncGeneratorWrapper((function*(){
     let res = yield new $ActionRecord($ActionEnum.AWAIT_VALUE, myPromise);
     yield new $ActionRecord($ActionEnum.YIELD_VALUE, res + 1);
   })());
 }
 

Method Summary

Modifier and Type	Method and Description
void	hotSwapScript(Node scriptRoot, Node originalRoot) Process the JS with root node root.
void	process(Node externs, Node root) Process the JS with root node root.
boolean	shouldTraverse(NodeTraversal nodeTraversal, Node n, Node parent) Visits a node in pre order (before visiting its children) and decides whether this node's children should be traversed.
void	visit(NodeTraversal t, Node n, Node parent) Visits a node in postorder (after its children have been visited).

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Method Detail

hotSwapScript

public void hotSwapScript(Node scriptRoot,
                          Node originalRoot)

Description copied from interface: HotSwapCompilerPass

Process the JS with root node root. This is supposed to be significantly faster compared to corresponding full-compiler passes.

Specified by:

hotSwapScript in interface HotSwapCompilerPass

Parameters:

scriptRoot - Root node corresponding to the file that is modified, should be of type Token.SCRIPT.

originalRoot - Root node corresponding to the original version of the file that is modified. Should be of type token.SCRIPT.

process

public void process(Node externs,
                    Node root)

Description copied from interface: CompilerPass

Process the JS with root node root. Can modify the contents of each Node tree

Specified by:

process in interface CompilerPass

Parameters:

externs - Top of external JS tree

root - Top of JS tree

shouldTraverse

public boolean shouldTraverse(NodeTraversal nodeTraversal,
                              Node n,
                              Node parent)

Description copied from interface: NodeTraversal.Callback

Visits a node in pre order (before visiting its children) and decides whether this node's children should be traversed. If children are traversed, they will be visited by NodeTraversal.Callback.visit(NodeTraversal, Node, Node) in postorder.

Implementations can have side effects (e.g. modifying the parse tree).

Specified by:

shouldTraverse in interface NodeTraversal.Callback

Returns:

whether the children of this node should be visited

visit

public void visit(NodeTraversal t,
                  Node n,
                  Node parent)

Description copied from interface: NodeTraversal.Callback

Visits a node in postorder (after its children have been visited). A node is visited only if all its parents should be traversed (NodeTraversal.Callback.shouldTraverse(NodeTraversal, Node, Node)).

Implementations can have side effects (e.g. modifying the parse tree).

Specified by:

visit in interface NodeTraversal.Callback