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keksAccountGUI/node_modulesOLD/regexp-tree/dist/traverse/index.js

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2019-08-11 18:48:02 +00:00
/**
* The MIT License (MIT)
* Copyright (c) 2017-present Dmitry Soshnikov <dmitry.soshnikov@gmail.com>
*/
'use strict';
var NodePath = require('./node-path');
/**
* Does an actual AST traversal, using visitor pattern,
* and calling set of callbacks.
*
* Based on https://github.com/olov/ast-traverse
*
* Expects AST in Mozilla Parser API: nodes which are supposed to be
* handled should have `type` property.
*
* @param Object root - a root node to start traversal from.
*
* @param Object options - an object with set of callbacks:
*
* - `pre(node, parent, prop, index)` - a hook called on node enter
* - `post`(node, parent, prop, index) - a hook called on node exit
* - `skipProperty(prop)` - a predicated whether a property should be skipped
*/
function astTraverse(root) {
var options = arguments.length > 1 && arguments[1] !== undefined ? arguments[1] : {};
var pre = options.pre;
var post = options.post;
var skipProperty = options.skipProperty;
function visit(node, parent, prop, idx) {
if (!node || typeof node.type !== 'string') {
return;
}
var res = undefined;
if (pre) {
res = pre(node, parent, prop, idx);
}
if (res !== false) {
// A node can be replaced during traversal, so we have to
// recalculate it from the parent, to avoid traversing "dead" nodes.
if (parent && parent[prop]) {
if (!isNaN(idx)) {
node = parent[prop][idx];
} else {
node = parent[prop];
}
}
for (var _prop in node) {
if (node.hasOwnProperty(_prop)) {
if (skipProperty ? skipProperty(_prop, node) : _prop[0] === '$') {
continue;
}
var child = node[_prop];
// Collection node.
//
// NOTE: a node (or several nodes) can be removed or inserted
// during traversal.
//
// Current traversing index is stored on top of the
// `NodePath.traversingIndexStack`. The stack is used to support
// recursive nature of the traversal.
//
// In this case `NodePath.traversingIndex` (which we use here) is
// updated in the NodePath remove/insert methods.
//
if (Array.isArray(child)) {
var index = 0;
NodePath.traversingIndexStack.push(index);
while (index < child.length) {
visit(child[index], node, _prop, index);
index = NodePath.updateTraversingIndex(+1);
}
NodePath.traversingIndexStack.pop();
}
// Simple node.
else {
visit(child, node, _prop);
}
}
}
}
if (post) {
post(node, parent, prop, idx);
}
}
visit(root, null);
}
module.exports = {
/**
* Traverses an AST.
*
* @param Object ast - an AST node
*
* @param Object | Array<Object> handlers:
*
* an object (or an array of objects)
*
* Each such object contains a handler function per node.
* In case of an array of handlers, they are applied in order.
* A handler may return a transformed node (or a different type).
*
* The per-node function may instead be an object with functions pre and post.
* pre is called before visiting the node, post after.
* If a handler is a function, it is treated as the pre function, with an empty post.
*
* @param Object options:
*
* a config object, specifying traversal options:
*
* `asNodes`: boolean - whether handlers should receives raw AST nodes
* (false by default), instead of a `NodePath` wrapper. Note, by default
* `NodePath` wrapper provides a set of convenient method to manipulate
* a traversing AST, and also has access to all parents list. A raw
* nodes traversal should be used in rare cases, when no `NodePath`
* features are needed.
*
* Special hooks:
*
* - `shouldRun(ast)` - a predicate determining whether the handler
* should be applied.
*
* NOTE: Multiple handlers are used as an optimization of applying all of
* them in one AST traversal pass.
*/
traverse: function traverse(ast, handlers) {
var options = arguments.length > 2 && arguments[2] !== undefined ? arguments[2] : { asNodes: false };
if (!Array.isArray(handlers)) {
handlers = [handlers];
}
// Filter out handlers by result of `shouldRun`, if the method is present.
handlers = handlers.filter(function (handler) {
if (typeof handler.shouldRun !== 'function') {
return true;
}
return handler.shouldRun(ast);
});
NodePath.initRegistry();
// Allow handlers to initializer themselves.
handlers.forEach(function (handler) {
if (typeof handler.init === 'function') {
handler.init(ast);
}
});
function getPathFor(node, parent, prop, index) {
var parentPath = NodePath.getForNode(parent);
var nodePath = NodePath.getForNode(node, parentPath, prop, index);
return nodePath;
}
// Handle actual nodes.
astTraverse(ast, {
/**
* Handler on node enter.
*/
pre: function pre(node, parent, prop, index) {
var nodePath = void 0;
if (!options.asNodes) {
nodePath = getPathFor(node, parent, prop, index);
}
var _iteratorNormalCompletion = true;
var _didIteratorError = false;
var _iteratorError = undefined;
try {
for (var _iterator = handlers[Symbol.iterator](), _step; !(_iteratorNormalCompletion = (_step = _iterator.next()).done); _iteratorNormalCompletion = true) {
var handler = _step.value;
// "Catch-all" `*` handler.
if (typeof handler['*'] === 'function') {
if (nodePath) {
// A path/node can be removed by some previous handler.
if (!nodePath.isRemoved()) {
var handlerResult = handler['*'](nodePath);
// Explicitly stop traversal.
if (handlerResult === false) {
return false;
}
}
} else {
handler['*'](node, parent, prop, index);
}
}
// Per-node handler.
var handlerFuncPre = void 0;
if (typeof handler[node.type] === 'function') {
handlerFuncPre = handler[node.type];
} else if (typeof handler[node.type] === 'object' && typeof handler[node.type].pre === 'function') {
handlerFuncPre = handler[node.type].pre;
}
if (handlerFuncPre) {
if (nodePath) {
// A path/node can be removed by some previous handler.
if (!nodePath.isRemoved()) {
var _handlerResult = handlerFuncPre.call(handler, nodePath);
// Explicitly stop traversal.
if (_handlerResult === false) {
return false;
}
}
} else {
handlerFuncPre.call(handler, node, parent, prop, index);
}
}
} // Loop over handlers
} catch (err) {
_didIteratorError = true;
_iteratorError = err;
} finally {
try {
if (!_iteratorNormalCompletion && _iterator.return) {
_iterator.return();
}
} finally {
if (_didIteratorError) {
throw _iteratorError;
}
}
}
},
// pre func
/**
* Handler on node exit.
*/
post: function post(node, parent, prop, index) {
if (!node) {
return;
}
var nodePath = void 0;
if (!options.asNodes) {
nodePath = getPathFor(node, parent, prop, index);
}
var _iteratorNormalCompletion2 = true;
var _didIteratorError2 = false;
var _iteratorError2 = undefined;
try {
for (var _iterator2 = handlers[Symbol.iterator](), _step2; !(_iteratorNormalCompletion2 = (_step2 = _iterator2.next()).done); _iteratorNormalCompletion2 = true) {
var handler = _step2.value;
// Per-node handler.
var handlerFuncPost = void 0;
if (typeof handler[node.type] === 'object' && typeof handler[node.type].post === 'function') {
handlerFuncPost = handler[node.type].post;
}
if (handlerFuncPost) {
if (nodePath) {
// A path/node can be removed by some previous handler.
if (!nodePath.isRemoved()) {
var handlerResult = handlerFuncPost.call(handler, nodePath);
// Explicitly stop traversal.
if (handlerResult === false) {
return false;
}
}
} else {
handlerFuncPost.call(handler, node, parent, prop, index);
}
}
} // Loop over handlers
} catch (err) {
_didIteratorError2 = true;
_iteratorError2 = err;
} finally {
try {
if (!_iteratorNormalCompletion2 && _iterator2.return) {
_iterator2.return();
}
} finally {
if (_didIteratorError2) {
throw _iteratorError2;
}
}
}
},
// post func
/**
* Skip locations by default.
*/
skipProperty: function skipProperty(prop) {
return prop === 'loc';
}
});
}
};