feat(utils): add getNodeAncestors

Author: jzabala

lib/util/getNodeAncestors.js

@@ -0,0 +1,21 @@
+'use strict';
+
+/**
+ * Returns the list of parents for the node, starting from the closest parent.
+ * @param {ASTNode} node - root node to start parent traversal
+ * @returns {Array.<ASTNode>} List of nodes or empty
+ */
+function getNodeAncestors(node) {
+  const ancestors = [];
+  if (!node) {
+    return ancestors;
+  }
+
+  // eslint-disable-next-line no-cond-assign
+  for (let parent = node; parent = parent.parent;) {
+    ancestors.push(parent);
+  }
+  return ancestors;
+}
+
+module.exports = getNodeAncestors;

tests/util/getNodeAncestors.js

@@ -0,0 +1,25 @@
+'use strict';
+
+const assert = require('assert');
+const getNodeAncestors = require('../../lib/util/getNodeAncestors');
+
+describe('getNodeAncestors', () => {
+  it('returns empty array for null node', () => {
+    assert.deepEqual(getNodeAncestors(null), []);
+  });
+  it('returns list of parents', () => {
+    const node = {
+      type: 'Identifier',
+      parent: {
+        type: 'FunctionDeclaration',
+        parent: {
+          type: 'Program'
+        }
+      }
+    };
+    const actual = getNodeAncestors(node);
+    const expected = ['FunctionDeclaration', 'Program'];
+
+    actual.forEach((parent, i) => assert.equal(parent.type, expected[i]));
+  });
+});