/**
* Some nodes (such as arrow functions) must be visited pre-order in order to rewrite the
* references to {@code this} correctly. Everything else is translated post-order in {@link
* #visit}.
*/
@Override
public boolean shouldTraverse(NodeTraversal t, Node n, Node parent) {
switch (n.getType()) {
case Token.FUNCTION:
if (n.isArrowFunction()) {
visitArrowFunction(t, n);
}
break;
case Token.CLASS:
// Need to check for super references before they get rewritten.
checkClassSuperReferences(n);
break;
case Token.PARAM_LIST:
visitParamList(n, parent);
break;
}
return true;
}
private void validateFunctionExpression(Node n) {
validateNodeType(Token.FUNCTION, n);
validateChildCount(n);
validateParameters(n.getChildAtIndex(1));
if (n.isArrowFunction()) {
validateEs6Feature("arrow functions", n);
validateEmptyName(n.getFirstChild());
if (n.getLastChild().getType() == Token.BLOCK) {
validateBlock(n.getLastChild());
} else {
validateExpression(n.getLastChild());
}
} else {
validateOptionalName(n.getFirstChild());
validateBlock(n.getLastChild());
}
}
/**
* Arrow functions must be visited pre-order in order to rewrite the references to {@code this}
* correctly. Everything else is translated post-order in {@link #visit}.
*/
@Override
public boolean shouldTraverse(NodeTraversal t, Node n, Node parent) {
switch (n.getType()) {
case Token.FUNCTION:
if (n.isArrowFunction()) {
visitArrowFunction(t, n);
}
break;
case Token.ARRAY_COMP:
case Token.ARRAY_PATTERN:
case Token.FOR_OF:
case Token.OBJECT_PATTERN:
case Token.SUPER:
cannotConvertYet(n, Token.name(n.getType()));
// Don't bother visiting the children of a node if we
// already know we can't convert the node itself.
return false;
}
return true;
}
private static boolean isDeclarationHelper(Node node) {
Node parent = node.getParent();
// Special case for class B extends A, A is not a declaration.
if (parent.isClass() && node != parent.getFirstChild()) {
return false;
}
// This condition can be true during InlineVariables.
if (parent.getParent() == null) {
return false;
}
if (NodeUtil.isNameDeclaration(parent.getParent()) && node == parent.getLastChild()) {
// Unless it is something like "for (var/let/const a of x){}",
// this is the RHS of a var/let/const and thus not a declaration.
if (parent.getParent().getParent() == null || !parent.getParent().getParent().isForOf()) {
return false;
}
}
// Special cases for destructuring patterns.
if (parent.isDestructuringPattern()
|| (parent.isStringKey() && parent.getParent().isObjectPattern())
|| (parent.isComputedProp()
&& parent.getParent().isObjectPattern()
&& node == parent.getLastChild())
|| (parent.isDefaultValue() && node == parent.getFirstChild())) {
return isDeclarationHelper(parent);
}
// Special case for arrow function
if (parent.isArrowFunction()) {
return node == parent.getFirstChild();
}
return DECLARATION_PARENTS.contains(parent.getType());
}
@Override
public boolean shouldTraverse(NodeTraversal t, Node n, Node parent) {
return !n.isFunction() || n.isArrowFunction();
}