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'use strict' |
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/** |
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* Crawl the given AST through the function walk(ast, callback) |
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*/ |
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function AstWalker () {} // eslint-disable-line
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/** |
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* visit all the AST nodes |
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* |
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* @param {Object} ast - AST node |
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* @param {Object or Function} callback - if (Function) the function will be called for every node. |
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* - if (Object) callback[<Node Type>] will be called for |
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* every node of type <Node Type>. callback["*"] will be called for all other nodes. |
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* in each case, if the callback returns false it does not descend into children. |
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* If no callback for the current type, children are visited. |
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*/ |
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AstWalker.prototype.walk = function (ast, callback) { |
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if (callback instanceof Function) { |
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callback = {'*': callback} |
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} |
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if (!('*' in callback)) { |
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callback['*'] = function () { return true } |
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} |
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const nodes = ast.nodes || (ast.body && ast.body.statements) || ast.declarations |
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if(ast.body && ast.initializationExpression) // 'for' loop handling
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nodes.push(ast.initializationExpression) |
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if (manageCallBack(ast, callback) && nodes && nodes.length > 0) { |
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for (let k in nodes) { |
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const child = nodes[k] |
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this.walk(child, callback) |
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} |
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} |
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} |
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/** |
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* walk the given @astList |
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* |
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* @param {Object} sourcesList - sources list (containing root AST node) |
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* @param {Function} - callback used by AstWalker to compute response |
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*/ |
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AstWalker.prototype.walkAstList = function (sourcesList, callback) { |
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const walker = new AstWalker() |
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for (let k in sourcesList) { |
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walker.walk(sourcesList[k].ast, callback) |
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} |
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} |
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function manageCallBack (node, callback) { |
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if (node.nodeType in callback) { |
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return callback[node.nodeType](node) |
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} |
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return callback['*'](node) |
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} |
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module.exports = AstWalker |
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