Function link

packages/pug-linker/index.js:11–69

(ast)

module.exports = link;
function link(ast) {
  assert(
    ast.type === 'Block',
    'The top level element should always be a block'
  );
  var extendsNode = null;
  if (ast.nodes.length) {
    var hasExtends = ast.nodes[0].type === 'Extends';
    checkExtendPosition(ast, hasExtends);
    if (hasExtends) {
      extendsNode = ast.nodes.shift();
    }
  }
  ast = applyIncludes(ast);
  ast.declaredBlocks = findDeclaredBlocks(ast);
  if (extendsNode) {
    var mixins = [];
    var expectedBlocks = [];
    ast.nodes.forEach(function addNode(node) {
      if (node.type === 'NamedBlock') {
        expectedBlocks.push(node);
      } else if (node.type === 'Block') {
        node.nodes.forEach(addNode);
      } else if (node.type === 'Mixin' && node.call === false) {
        mixins.push(node);
      } else {
        error(
          'UNEXPECTED_NODES_IN_EXTENDING_ROOT',
          'Only named blocks and mixins can appear at the top level of an extending template',
          node
        );
      }
    });
    var parent = link(extendsNode.file.ast);
    extend(parent.declaredBlocks, ast);
    var foundBlockNames = [];
    walk(parent, function(node) {
      if (node.type === 'NamedBlock') {
        foundBlockNames.push(node.name);
      }
    });
    expectedBlocks.forEach(function(expectedBlock) {
      if (foundBlockNames.indexOf(expectedBlock.name) === -1) {
        error(
          'UNEXPECTED_BLOCK',
          'Unexpected block ' + expectedBlock.name,
          expectedBlock
        );
      }
    });
    Object.keys(ast.declaredBlocks).forEach(function(name) {
      parent.declaredBlocks[name] = ast.declaredBlocks[name];
    });
    parent.nodes = mixins.concat(parent.nodes);
    parent.hasExtends = true;
    return parent;
  }
  return ast;