96 lines
2.4 KiB
JavaScript
96 lines
2.4 KiB
JavaScript
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import { createPath } from "./node-path";
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import { unionTypesMap, nodeAndUnionTypes } from "./nodes"; // recursively walks the AST starting at the given node. The callback is invoked for
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// and object that has a 'type' property.
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function walk(context, callback) {
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var stop = false;
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function innerWalk(context, callback) {
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if (stop) {
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return;
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}
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var node = context.node;
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if (node === undefined) {
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console.warn("traversing with an empty context");
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return;
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}
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if (node._deleted === true) {
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return;
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}
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var path = createPath(context);
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callback(node.type, path);
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if (path.shouldStop) {
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stop = true;
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return;
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}
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Object.keys(node).forEach(function (prop) {
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var value = node[prop];
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if (value === null || value === undefined) {
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return;
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}
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var valueAsArray = Array.isArray(value) ? value : [value];
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valueAsArray.forEach(function (childNode) {
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if (typeof childNode.type === "string") {
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var childContext = {
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node: childNode,
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parentKey: prop,
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parentPath: path,
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shouldStop: false,
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inList: Array.isArray(value)
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};
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innerWalk(childContext, callback);
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}
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});
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});
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}
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innerWalk(context, callback);
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}
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var noop = function noop() {};
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export function traverse(node, visitors) {
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var before = arguments.length > 2 && arguments[2] !== undefined ? arguments[2] : noop;
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var after = arguments.length > 3 && arguments[3] !== undefined ? arguments[3] : noop;
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Object.keys(visitors).forEach(function (visitor) {
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if (!nodeAndUnionTypes.includes(visitor)) {
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throw new Error("Unexpected visitor ".concat(visitor));
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}
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});
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var context = {
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node: node,
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inList: false,
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shouldStop: false,
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parentPath: null,
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parentKey: null
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};
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walk(context, function (type, path) {
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if (typeof visitors[type] === "function") {
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before(type, path);
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visitors[type](path);
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after(type, path);
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}
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var unionTypes = unionTypesMap[type];
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if (!unionTypes) {
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throw new Error("Unexpected node type ".concat(type));
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}
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unionTypes.forEach(function (unionType) {
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if (typeof visitors[unionType] === "function") {
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before(unionType, path);
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visitors[unionType](path);
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after(unionType, path);
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}
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});
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});
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}
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