diff --git a/lib/utils/templatize.js b/lib/utils/templatize.js
index 14b5eeb6fe..581949e98f 100644
--- a/lib/utils/templatize.js
+++ b/lib/utils/templatize.js
@@ -112,6 +112,7 @@ class TemplateInstanceBase extends base {
   constructor(props) {
     super();
     this._configureProperties(props);
+    /** @type {!StampedTemplate} */
     this.root = this._stampTemplate(this.__dataHost);
     // Save list of stamped children
     let children = this.children = [];
diff --git a/package-lock.json b/package-lock.json
index 37902fd39f..1d6a14320c 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -12721,15 +12721,13 @@
               "version": "1.0.0",
               "resolved": "https://registry.npmjs.org/balanced-match/-/balanced-match-1.0.0.tgz",
               "integrity": "sha1-ibTRmasr7kneFk6gK4nORi1xt2c=",
-              "dev": true,
-              "optional": true
+              "dev": true
             },
             "brace-expansion": {
               "version": "1.1.11",
               "resolved": "https://registry.npmjs.org/brace-expansion/-/brace-expansion-1.1.11.tgz",
               "integrity": "sha512-iCuPHDFgrHX7H2vEI/5xpz07zSHB00TpugqhmYtVmMO6518mCuRMoOYFldEBl0g187ufozdaHgWKcYFb61qGiA==",
               "dev": true,
-              "optional": true,
               "requires": {
                 "balanced-match": "^1.0.0",
                 "concat-map": "0.0.1"
@@ -12746,22 +12744,19 @@
               "version": "1.1.0",
               "resolved": "https://registry.npmjs.org/code-point-at/-/code-point-at-1.1.0.tgz",
               "integrity": "sha1-DQcLTQQ6W+ozovGkDi7bPZpMz3c=",
-              "dev": true,
-              "optional": true
+              "dev": true
             },
             "concat-map": {
               "version": "0.0.1",
               "resolved": "https://registry.npmjs.org/concat-map/-/concat-map-0.0.1.tgz",
               "integrity": "sha1-2Klr13/Wjfd5OnMDajug1UBdR3s=",
-              "dev": true,
-              "optional": true
+              "dev": true
             },
             "console-control-strings": {
               "version": "1.1.0",
               "resolved": "https://registry.npmjs.org/console-control-strings/-/console-control-strings-1.1.0.tgz",
               "integrity": "sha1-PXz0Rk22RG6mRL9LOVB/mFEAjo4=",
-              "dev": true,
-              "optional": true
+              "dev": true
             },
             "core-util-is": {
               "version": "1.0.2",
@@ -12892,8 +12887,7 @@
               "version": "2.0.3",
               "resolved": "https://registry.npmjs.org/inherits/-/inherits-2.0.3.tgz",
               "integrity": "sha1-Yzwsg+PaQqUC9SRmAiSA9CCCYd4=",
-              "dev": true,
-              "optional": true
+              "dev": true
             },
             "ini": {
               "version": "1.3.5",
@@ -12907,7 +12901,6 @@
               "resolved": "https://registry.npmjs.org/is-fullwidth-code-point/-/is-fullwidth-code-point-1.0.0.tgz",
               "integrity": "sha1-754xOG8DGn8NZDr4L95QxFfvAMs=",
               "dev": true,
-              "optional": true,
               "requires": {
                 "number-is-nan": "^1.0.0"
               }
@@ -12924,7 +12917,6 @@
               "resolved": "https://registry.npmjs.org/minimatch/-/minimatch-3.0.4.tgz",
               "integrity": "sha512-yJHVQEhyqPLUTgt9B83PXu6W3rx4MvvHvSUvToogpwoGDOUQ+yDrR0HRot+yOCdCO7u4hX3pWft6kWBBcqh0UA==",
               "dev": true,
-              "optional": true,
               "requires": {
                 "brace-expansion": "^1.1.7"
               }
@@ -12933,15 +12925,13 @@
               "version": "0.0.8",
               "resolved": "https://registry.npmjs.org/minimist/-/minimist-0.0.8.tgz",
               "integrity": "sha1-hX/Kv8M5fSYluCKCYuhqp6ARsF0=",
-              "dev": true,
-              "optional": true
+              "dev": true
             },
             "minipass": {
               "version": "2.2.4",
               "resolved": "https://registry.npmjs.org/minipass/-/minipass-2.2.4.tgz",
               "integrity": "sha512-hzXIWWet/BzWhYs2b+u7dRHlruXhwdgvlTMDKC6Cb1U7ps6Ac6yQlR39xsbjWJE377YTCtKwIXIpJ5oP+j5y8g==",
               "dev": true,
-              "optional": true,
               "requires": {
                 "safe-buffer": "^5.1.1",
                 "yallist": "^3.0.0"
@@ -12962,7 +12952,6 @@
               "resolved": "https://registry.npmjs.org/mkdirp/-/mkdirp-0.5.1.tgz",
               "integrity": "sha1-MAV0OOrGz3+MR2fzhkjWaX11yQM=",
               "dev": true,
-              "optional": true,
               "requires": {
                 "minimist": "0.0.8"
               }
@@ -13051,8 +13040,7 @@
               "version": "1.0.1",
               "resolved": "https://registry.npmjs.org/number-is-nan/-/number-is-nan-1.0.1.tgz",
               "integrity": "sha1-CXtgK1NCKlIsGvuHkDGDNpQaAR0=",
-              "dev": true,
-              "optional": true
+              "dev": true
             },
             "object-assign": {
               "version": "4.1.1",
@@ -13066,7 +13054,6 @@
               "resolved": "https://registry.npmjs.org/once/-/once-1.4.0.tgz",
               "integrity": "sha1-WDsap3WWHUsROsF9nFC6753Xa9E=",
               "dev": true,
-              "optional": true,
               "requires": {
                 "wrappy": "1"
               }
@@ -13204,7 +13191,6 @@
               "resolved": "https://registry.npmjs.org/string-width/-/string-width-1.0.2.tgz",
               "integrity": "sha1-EYvfW4zcUaKn5w0hHgfisLmxB9M=",
               "dev": true,
-              "optional": true,
               "requires": {
                 "code-point-at": "^1.0.0",
                 "is-fullwidth-code-point": "^1.0.0",