Files F102344367

traverse.js
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Created: Wed, Feb 19, 17:36

traverse.js
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	import { createPath } from "./node-path";
	import { unionTypesMap, nodeAndUnionTypes } from "./nodes"; // recursively walks the AST starting at the given node. The callback is invoked for
	// and object that has a 'type' property.

	function walk(context, callback) {
	var stop = false;

	function innerWalk(context, callback) {
	if (stop) {
	return;
	}

	var node = context.node;

	if (node === undefined) {
	console.warn("traversing with an empty context");
	return;
	}

	if (node._deleted === true) {
	return;
	}

	var path = createPath(context);
	callback(node.type, path);

	if (path.shouldStop) {
	stop = true;
	return;
	}

	Object.keys(node).forEach(function (prop) {
	var value = node[prop];

	if (value === null \|\| value === undefined) {
	return;
	}

	var valueAsArray = Array.isArray(value) ? value : [value];
	valueAsArray.forEach(function (childNode) {
	if (typeof childNode.type === "string") {
	var childContext = {
	node: childNode,
	parentKey: prop,
	parentPath: path,
	shouldStop: false,
	inList: Array.isArray(value)
	};
	innerWalk(childContext, callback);
	}
	});
	});
	}

	innerWalk(context, callback);
	}

	var noop = function noop() {};

	export function traverse(node, visitors) {
	var before = arguments.length > 2 && arguments[2] !== undefined ? arguments[2] : noop;
	var after = arguments.length > 3 && arguments[3] !== undefined ? arguments[3] : noop;
	Object.keys(visitors).forEach(function (visitor) {
	if (!nodeAndUnionTypes.includes(visitor)) {
	throw new Error("Unexpected visitor ".concat(visitor));
	}
	});
	var context = {
	node: node,
	inList: false,
	shouldStop: false,
	parentPath: null,
	parentKey: null
	};
	walk(context, function (type, path) {
	if (typeof visitors[type] === "function") {
	before(type, path);
	visitors[type](path);
	after(type, path);
	}

	var unionTypes = unionTypesMap[type];

	if (!unionTypes) {
	throw new Error("Unexpected node type ".concat(type));
	}

	unionTypes.forEach(function (unionType) {
	if (typeof visitors[unionType] === "function") {
	before(unionType, path);
	visitors[unionType](path);
	after(unionType, path);
	}
	});
	});
	}

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