NodeTraversal (Closure Compiler v20150126 API)

java.lang.Object
- com.google.javascript.jscomp.NodeTraversal

```
public class NodeTraversal
extends Object
```
NodeTraversal allows an iteration through the nodes in the parse tree, and facilitates the optimizations on the parse tree.

Nested Class Summary

Nested Classes
Modifier and Type	Class and Description
`static class`	`NodeTraversal.AbstractNodeTypePruningCallback` Abstract callback to visit a pruned set of nodes.
`static class`	`NodeTraversal.AbstractPostOrderCallback` Abstract callback to visit all nodes in postorder.
`static class`	`NodeTraversal.AbstractPreOrderCallback` Abstract callback to visit all nodes in preorder.
`static class`	`NodeTraversal.AbstractScopedCallback` Abstract scoped callback to visit all nodes in postorder.
`static class`	`NodeTraversal.AbstractShallowCallback` Abstract callback to visit all nodes but not traverse into function bodies.
`static class`	`NodeTraversal.AbstractShallowStatementCallback` Abstract callback to visit all structure and statement nodes but doesn't traverse into functions or expressions.
`static interface`	`NodeTraversal.Callback` Callback for tree-based traversals
`static interface`	`NodeTraversal.FunctionCallback` Callback for passes that iterate over a list of functions
`static interface`	`NodeTraversal.ScopedCallback` Callback that also knows about scope changes

Field Summary

Fields
Modifier and Type Field and Description

static DiagnosticType NODE_TRAVERSAL_ERROR

Fields
Modifier and Type	Field and Description
`static DiagnosticType`	`NODE_TRAVERSAL_ERROR`

Constructor Summary

Constructors
Constructor and Description
`NodeTraversal(AbstractCompiler compiler, NodeTraversal.Callback cb)` Creates a node traversal using the specified callback interface.
`NodeTraversal(AbstractCompiler compiler, NodeTraversal.Callback cb, com.google.javascript.jscomp.ScopeCreator scopeCreator)` Creates a node traversal using the specified callback interface and the scope creator.

Method Summary

All Methods Static Methods Instance Methods Concrete Methods
Modifier and Type	Method and Description
`int`	`getCharno()` Gets the current char number, or zero if it cannot be determined.
`AbstractCompiler`	`getCompiler()`
`ControlFlowGraph<Node>`	`getControlFlowGraph()` Gets the control flow graph for the current JS scope.
`Node`	`getCurrentNode()` Returns the node currently being traversed.
`Node`	`getEnclosingFunction()` Examines the functions stack for the last instance of a function node.
`CompilerInput`	`getInput()` Gets the current input source.
`int`	`getLineNumber()` Gets the current line number, or zero if it cannot be determined.
`JSModule`	`getModule()` Gets the current input module.
`Scope`	`getScope()` Gets the current scope.
`Node`	`getScopeRoot()` Returns the current scope's root.
`String`	`getSourceName()` Gets the current input source name.
`boolean`	`hasScope()`
`JSError`	`makeError(Node n, CheckLevel level, DiagnosticType type, String... arguments)` Creates a JSError during NodeTraversal.
`JSError`	`makeError(Node n, DiagnosticType type, String... arguments)` Creates a JSError during NodeTraversal.
`void`	`report(Node n, DiagnosticType diagnosticType, String... arguments)` Reports a diagnostic (error or warning)
`static void`	`traverse(AbstractCompiler compiler, Node root, NodeTraversal.Callback cb)` Traverses a node recursively.
`void`	`traverse(Node root)` Traverses a parse tree recursively.
`static void`	`traverseChangedFunctions(AbstractCompiler compiler, NodeTraversal.FunctionCallback callback)` Traversal for passes that work only on changed functions.
`protected void`	`traverseInnerNode(Node node, Node parent, Scope refinedScope)` Traverses an inner node recursively with a refined scope.
`static void`	`traverseRoots(AbstractCompiler compiler, List<Node> roots, NodeTraversal.Callback cb)` Traverses a list of node trees.
`static void`	`traverseRoots(AbstractCompiler compiler, NodeTraversal.Callback cb, Node... roots)`
`void`	`traverseRoots(List<Node> roots)`
`void`	`traverseRoots(Node... roots)`

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Field Detail
  - NODE_TRAVERSAL_ERROR
```
public static final DiagnosticType NODE_TRAVERSAL_ERROR
```
- Constructor Detail
  - NodeTraversal
```
public NodeTraversal(AbstractCompiler compiler,
                     NodeTraversal.Callback cb)
```
    Creates a node traversal using the specified callback interface.
  - NodeTraversal
```
public NodeTraversal(AbstractCompiler compiler,
                     NodeTraversal.Callback cb,
                     com.google.javascript.jscomp.ScopeCreator scopeCreator)
```
    Creates a node traversal using the specified callback interface and the scope creator.
- Method Detail
  - traverse
```
public void traverse(Node root)
```
    Traverses a parse tree recursively.
  - traverseRoots
```
public void traverseRoots(Node... roots)
```
  - traverseRoots
```
public void traverseRoots(List<Node> roots)
```
  - traverseInnerNode
```
protected void traverseInnerNode(Node node,
                                 Node parent,
                                 Scope refinedScope)
```
    Traverses an inner node recursively with a refined scope. An inner node may be any node with a non null parent (i.e. all nodes except the root).
    
    Parameters:
    
    node - the node to traverse
    
    parent - the node's parent, it may not be null
    
    refinedScope - the refined scope of the scope currently at the top of the scope stack or in trivial cases that very scope or null
  - getCompiler
```
public AbstractCompiler getCompiler()
```
  - getLineNumber
```
public int getLineNumber()
```
    Gets the current line number, or zero if it cannot be determined. The line number is retrieved lazily as a running time optimization.
  - getCharno
```
public int getCharno()
```
    Gets the current char number, or zero if it cannot be determined. The line number is retrieved lazily as a running time optimization.
  - getSourceName
```
public String getSourceName()
```
    Gets the current input source name.
    
    Returns:
    
    A string that may be empty, but not null
  - getInput
```
public CompilerInput getInput()
```
    Gets the current input source.
  - getModule
```
public JSModule getModule()
```
    Gets the current input module.
  - getCurrentNode
```
public Node getCurrentNode()
```
    Returns the node currently being traversed.
  - traverseChangedFunctions
```
public static void traverseChangedFunctions(AbstractCompiler compiler,
                                            NodeTraversal.FunctionCallback callback)
```
    Traversal for passes that work only on changed functions. Suppose a loopable pass P1 uses this traversal. Then, if a function doesn't change between two runs of P1, it won't look at the function the second time. (We're assuming that P1 runs to a fixpoint, o/w we may miss optimizations.)
    Most changes are reported with calls to Compiler.reportCodeChange(), which doesn't know which scope changed. We keep track of the current scope by calling Compiler.setScope inside pushScope and popScope. The automatic tracking can be wrong in rare cases when a pass changes scope w/out causing a call to pushScope or popScope. It's very hard to find the places where this happens unless a bug is triggered. Passes that do cross-scope modifications call Compiler.reportChangeToEnclosingScope(Node n).
  - traverse
```
public static void traverse(AbstractCompiler compiler,
                            Node root,
                            NodeTraversal.Callback cb)
```
    Traverses a node recursively.
  - traverseRoots
```
public static void traverseRoots(AbstractCompiler compiler,
                                 List<Node> roots,
                                 NodeTraversal.Callback cb)
```
    Traverses a list of node trees.
  - traverseRoots
```
public static void traverseRoots(AbstractCompiler compiler,
                                 NodeTraversal.Callback cb,
                                 Node... roots)
```
  - getEnclosingFunction
```
public Node getEnclosingFunction()
```
    Examines the functions stack for the last instance of a function node.
  - getScope
```
public Scope getScope()
```
    Gets the current scope.
  - getControlFlowGraph
```
public ControlFlowGraph<Node> getControlFlowGraph()
```
    Gets the control flow graph for the current JS scope.
  - getScopeRoot
```
public Node getScopeRoot()
```
    Returns the current scope's root.
  - hasScope
```
public boolean hasScope()
```
  - report
```
public void report(Node n,
                   DiagnosticType diagnosticType,
                   String... arguments)
```
    Reports a diagnostic (error or warning)
  - makeError
```
public JSError makeError(Node n,
                         CheckLevel level,
                         DiagnosticType type,
                         String... arguments)
```
    Creates a JSError during NodeTraversal.
    
    Parameters:
    
    n - Determines the line and char position within the source file name
    
    type - The DiagnosticType
    
    arguments - Arguments to be incorporated into the message
  - makeError
```
public JSError makeError(Node n,
                         DiagnosticType type,
                         String... arguments)
```
    Creates a JSError during NodeTraversal.
    
    Parameters:
    
    n - Determines the line and char position within the source file name
    
    type - The DiagnosticType
    
    arguments - Arguments to be incorporated into the message

Class NodeTraversal

Nested Class Summary

Field Summary

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Field Detail

NODE_TRAVERSAL_ERROR

Constructor Detail

NodeTraversal

NodeTraversal

Method Detail

traverse

traverseRoots

traverseRoots

traverseInnerNode

getCompiler

getLineNumber

getCharno

getSourceName

getInput

getModule

getCurrentNode

traverseChangedFunctions

traverse

traverseRoots

traverseRoots

getEnclosingFunction

getScope

getControlFlowGraph

getScopeRoot

hasScope

report

makeError

makeError