const Node = require('./node');
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class Container extends Node {
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walk(callback) {
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return this.each((child, i) => {
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let result = callback(child, i);
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if (result !== false && child.walk) {
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result = child.walk(callback);
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}
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return result;
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});
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}
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walkType(type, callback) {
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if (!type || !callback) {
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throw new Error('Parameters {type} and {callback} are required.');
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}
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// allow users to pass a constructor, or node type string; eg. Word.
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const isTypeCallable = typeof type === 'function';
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return this.walk((node, index) => {
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if ((isTypeCallable && node instanceof type) || (!isTypeCallable && node.type === type)) {
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return callback.call(this, node, index);
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}
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});
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}
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}
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Container.registerWalker = (constructor) => {
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let walkerName = `walk${constructor.name}`;
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// plural sugar
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if (walkerName.lastIndexOf('s') !== walkerName.length - 1) {
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walkerName += 's';
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}
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if (Container.prototype[walkerName]) {
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return;
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}
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// we need access to `this` so we can't use an arrow function
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Container.prototype[walkerName] = function(callback) {
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return this.walkType(constructor, callback);
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};
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};
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module.exports = Container;
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