Function FindPrecedingTokenEx

internal/astnav/tokens.go:332–452

(sourceFile *ast.SourceFile, position int, startNode *ast.Node, excludeJSDoc bool)

}

func FindPrecedingTokenEx(sourceFile *ast.SourceFile, position int, startNode *ast.Node, excludeJSDoc bool) *ast.Node {
	var find func(node *ast.Node) *ast.Node
	find = func(n *ast.Node) *ast.Node {
		if ast.IsNonWhitespaceToken(n) && n.Kind != ast.KindEndOfFile {
			return n
		}

		// `foundChild` is the leftmost node that contains the target position.
		// `prevChild` is the last visited child of the current node.
		var foundChild, prevChild *ast.Node
		visitNode := func(node *ast.Node, _ *ast.NodeVisitor) *ast.Node {
			// skip synthesized nodes (that will exist now because of jsdoc handling)
			if node == nil || node.Flags&ast.NodeFlagsReparsed != 0 {
				return node
			}
			if foundChild != nil { // We cannot abort visiting children, so once the desired child is found, we do nothing.
				return node
			}
			if position < node.End() && (prevChild == nil || prevChild.End() <= position) {
				foundChild = node
			} else {
				prevChild = node
			}
			return node
		}
		visitNodes := func(nodeList *ast.NodeList, _ *ast.NodeVisitor) *ast.NodeList {
			if foundChild != nil {
				return nodeList
			}
			if nodeList != nil && len(nodeList.Nodes) > 0 {
				nodes := nodeList.Nodes
				index, match := core.BinarySearchUniqueFunc(nodes, func(middle int, _ *ast.Node) int {
					// synthetic jsdoc nodes should have jsdocNode.End() <= n.Pos()
					if nodes[middle].Flags&ast.NodeFlagsReparsed != 0 {
						return comparisonLessThan
					}
					if position < nodes[middle].End() {
						if middle == 0 || position >= nodes[middle-1].End() {
							return comparisonEqualTo
						}
						return comparisonGreaterThan
					}
					return comparisonLessThan
				})

				if match {
					foundChild = nodes[index]
				}

				validLookupIndex := core.IfElse(match, index-1, len(nodes)-1)
				for i := validLookupIndex; i >= 0; i-- {
					if nodes[i].Flags&ast.NodeFlagsReparsed != 0 {
						continue
					}
					if prevChild == nil {
						prevChild = nodes[i]
					}
				}