var VISITOR_KEYS = require("./visitor-keys");
var _ = require("lodash");
var traverse = module.exports = function (parent, callbacks, blacklistTypes) {
Iif (!parent) return;
if (_.isArray(parent)) {
_.each(parent, function (node) {
traverse(node, callbacks, blacklistTypes);
});
return;
}
var keys = VISITOR_KEYS[parent.type] || [];
blacklistTypes = blacklistTypes || [];
if (_.isFunction(callbacks)) {
callbacks = { enter: callbacks };
}
_.each(keys, function (key) {
var nodes = parent[key];
if (!nodes) return;
var handle = function (obj, key) {
var node = obj[key];
if (!node) return;
// type is blacklisted
if (blacklistTypes.indexOf(node.type) >= 0) return;
// enter
var result = callbacks.enter(node, parent, obj, key);
// stop iteration
if (result === false) return;
// replace node
if (result != null) node = obj[key] = result;
traverse(node, callbacks, blacklistTypes);
// exit
if (callbacks.exit) callbacks.exit(node, parent, obj, key);
};
if (_.isArray(nodes)) {
_.each(nodes, function (node, i) {
handle(nodes, i);
});
// remove deleted nodes
parent[key] = _.flatten(parent[key]).filter(function (node) {
return node !== traverse.Delete;
});
} else {
handle(parent, key);
Iif (parent[key] === traverse.Delete) {
throw new Error("trying to delete property " + key + " from " +
parent.type + " but can't because it's required");
}
}
});
};
traverse.Delete = {};
traverse.hasType = function (tree, type, blacklistTypes) {
if (tree.type === type) return true;
var has = false;
blacklistTypes = blacklistTypes || [];
if (_.isArray(tree)) {
return !!_.find(tree, function (node) {
return traverse.hasType(node, type, blacklistTypes);
});
} else {
traverse(tree, function (node) {
if (node.type === type) {
has = true;
return false;
}
}, blacklistTypes);
}
return has;
};
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