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2 years ago
'use strict';
module.exports = walkAST;
function walkAST(ast, before, after, options) {
if (after && typeof after === 'object' && typeof options === 'undefined') {
options = after;
after = null;
}
options = options || {includeDependencies: false};
var parents = (options.parents = options.parents || []);
var replace = function replace(replacement) {
if (Array.isArray(replacement) && !replace.arrayAllowed) {
throw new Error(
'replace() can only be called with an array if the last parent is a Block or NamedBlock'
);
}
ast = replacement;
};
replace.arrayAllowed =
parents[0] &&
(/^(Named)?Block$/.test(parents[0].type) ||
(parents[0].type === 'RawInclude' && ast.type === 'IncludeFilter'));
if (before) {
var result = before(ast, replace);
if (result === false) {
return ast;
} else if (Array.isArray(ast)) {
// return right here to skip after() call on array
return walkAndMergeNodes(ast);
}
}
parents.unshift(ast);
switch (ast.type) {
case 'NamedBlock':
case 'Block':
ast.nodes = walkAndMergeNodes(ast.nodes);
break;
case 'Case':
case 'Filter':
case 'Mixin':
case 'Tag':
case 'InterpolatedTag':
case 'When':
case 'Code':
case 'While':
if (ast.block) {
ast.block = walkAST(ast.block, before, after, options);
}
break;
case 'Each':
if (ast.block) {
ast.block = walkAST(ast.block, before, after, options);
}
if (ast.alternate) {
ast.alternate = walkAST(ast.alternate, before, after, options);
}
break;
case 'EachOf':
if (ast.block) {
ast.block = walkAST(ast.block, before, after, options);
}
break;
case 'Conditional':
if (ast.consequent) {
ast.consequent = walkAST(ast.consequent, before, after, options);
}
if (ast.alternate) {
ast.alternate = walkAST(ast.alternate, before, after, options);
}
break;
case 'Include':
walkAST(ast.block, before, after, options);
walkAST(ast.file, before, after, options);
break;
case 'Extends':
walkAST(ast.file, before, after, options);
break;
case 'RawInclude':
ast.filters = walkAndMergeNodes(ast.filters);
walkAST(ast.file, before, after, options);
break;
case 'Attrs':
case 'BlockComment':
case 'Comment':
case 'Doctype':
case 'IncludeFilter':
case 'MixinBlock':
case 'YieldBlock':
case 'Text':
break;
case 'FileReference':
if (options.includeDependencies && ast.ast) {
walkAST(ast.ast, before, after, options);
}
break;
default:
throw new Error('Unexpected node type ' + ast.type);
break;
}
parents.shift();
after && after(ast, replace);
return ast;
function walkAndMergeNodes(nodes) {
return nodes.reduce(function(nodes, node) {
var result = walkAST(node, before, after, options);
if (Array.isArray(result)) {
return nodes.concat(result);
} else {
return nodes.concat([result]);
}
}, []);
}
}