eslint/tests/lib/shared/traverser.js

   1 "use strict";
   2
   3 const assert = require("chai").assert;
   4 const Traverser = require("../../../lib/shared/traverser");
   5
   6 describe("Traverser", () => {
   7     it("traverses all keys except 'parent', 'leadingComments', and 'trailingComments'", () => {
   8         const traverser = new Traverser();
   9         const fakeAst = {
  10             type: "Program",
  11             body: [
  12                 {
  13                     type: "ExpressionStatement",
  14                     leadingComments: {
  15                         type: "Line"
  16                     },
  17                     trailingComments: {
  18                         type: "Block"
  19                     }
  20                 },
  21                 {
  22                     type: "FooStatement",
  23                     foo: {
  24                         type: "BarStatement"
  25                     }
  26                 }
  27             ]
  28         };
  29
  30         fakeAst.body[0].parent = fakeAst;
  31
  32         const enteredNodes = [];
  33         const exitedNodes = [];
  34
  35         traverser.traverse(fakeAst, {
  36             enter: node => enteredNodes.push(node),
  37             leave: node => exitedNodes.push(node)
  38         });
  39
  40         assert.deepStrictEqual(enteredNodes, [fakeAst, fakeAst.body[0], fakeAst.body[1], fakeAst.body[1].foo]);
  41         assert.deepStrictEqual(exitedNodes, [fakeAst.body[0], fakeAst.body[1].foo, fakeAst.body[1], fakeAst]);
  42     });
  43
  44     it("traverses AST as using 'visitorKeys' option if given", () => {
  45         const traverser = new Traverser();
  46         const fakeAst = {
  47             type: "Program",
  48             body: [
  49                 {
  50                     type: "ClassDeclaration",
  51                     id: {
  52                         type: "Identifier"
  53                     },
  54                     superClass: null,
  55                     body: {
  56                         type: "ClassBody",
  57                         body: []
  58                     },
  59                     experimentalDecorators: [
  60                         {
  61                             type: "Decorator",
  62                             expression: {}
  63                         }
  64                     ]
  65                 }
  66             ]
  67         };
  68
  69         fakeAst.body[0].parent = fakeAst;
  70
  71         const visited = [];
  72
  73         // with 'visitorKeys' option to traverse decorators.
  74         traverser.traverse(fakeAst, {
  75             enter: node => visited.push(node.type),
  76             visitorKeys: Object.assign({}, Traverser.DEFAULT_VISITOR_KEYS, {
  77                 ClassDeclaration: Traverser.DEFAULT_VISITOR_KEYS.ClassDeclaration.concat(["experimentalDecorators"])
  78             })
  79         });
  80         assert.deepStrictEqual(visited, ["Program", "ClassDeclaration", "Identifier", "ClassBody", "Decorator"]);
  81     });
  82 });