Visit nodes in the tree.
Visit a single node:
var Visitor = require('tree-visitor');
var node = { type: 'number', value: 1 };
function MyVisitor() {}
MyVisitor.prototype = new Visitor();
MyVisitor.prototype.visit_number = function (number) {
console.log(number.value);
};
var myVisitor = new MyVisitor();
myVisitor.visit(node); // 1Visit an array of nodes:
var Visitor = require('tree-visitor');
var nodes = [
{ type: 'number', value: 1 },
{ type: 'string', value: 'abc', quote: '"' }
];
function MyVisitor() {}
MyVisitor.prototype = new Visitor();
MyVisitor.prototype.visit_number = function (number) {
console.log(number.value);
};
MyVisitor.prototype.visit_string = function (string) {
console.log(string.quote string.value string.quote);
};
var myVisitor = new MyVisitor();
myVisitor.visit(nodes); // 1 "abc"Visit nested nodes:
var Visitor = require('tree-visitor');
var number = { type: 'number', value: 1 };
var string = { type: 'string', value: 'abc' };
var expression = {
type: 'binaryExpression',
operator: ' ',
left: number,
right: string
};
function MyVisitor() {}
MyVisitor.prototype = new Visitor();
MyVisitor.prototype.visit_binaryExpression = function (binaryExpression) {
this.visit(binaryExpression.left);
console.log(binaryExpression.operator);
this.visit(binaryExpression.right);
};
MyVisitor.prototype.visit_number = function (number) {
console.log(number.value);
};
MyVisitor.prototype.visit_string = function (string) {
console.log(string.quote string.value string.quote);
};
var myVisitor = new MyVisitor();
myVisitor.visit(expression); // 1 "abc"One method to rule them all:
var Visitor = require('tree-visitor');
var nodes = [
{ type: 'number', value: 1 },
{ type: 'string', value: 'abc', quote: '"' }
];
function MyVisitor() {}
MyVisitor.prototype = new Visitor();
MyVisitor.prototype.visit_node = function (node) {
console.log(node.value);
};
var myVisitor = new MyVisitor();
myVisitor.visit(nodes); // 1 abcvar Visitor = require('tree-visitor');
function MyVisitor() {}
MyVisitor.prototype = new Visitor();
MyVisitor.prototype.visit_nodeType = function (node) {};
var myVisitor = new MyVisitor();
myVisitor.visit(node);Visitor should be "subclassed" by a constructor, the new constructor should have methods like .visit_nodeType(), and the node being visited should have a type property. If the value of type and the string after .visit_ matches, the node will be passed to that method when calling .visit(node).
Either a single node (any js object), or an array of nodes can be visited. In the latter case, the nodes are visited sequentially.
.visit_node() is a special method, if the node being visited doesn't have a corresponding method, it's passed to .visit_node(). If it does, however, it will not be passed to this method.
Nodes that are not a plain object (e.g., string, null, etc) or don't have a type property are ignored (i.e., it's not passed to any method, not even .visit_node()).
When visiting a single node, the returning value of .visit(node) is the returning value of the corresponding method, or the node itself if it doesn't have a corresponding method.
When visiting an array of nodes, the returning value of .visit(nodes) is the original array (i.e., nodes).